Geotechnical Engineering Report - apps.larimer.org Engineering Report South Shore Carter Lake Campground Expansion Larimer County, Colorado July 15, 2016 Terracon Project No. 20165057

Geotechnical Engineering Report South Shore Carter Lake Campground Expansion

Northwest of CR 31 and Cougar Run Lane

Larimer County, Colorado

July 15, 2016

Terracon Project No. 20165057

Prepared for:

Larimer County Colorado

Fort Collins, Colorado

Prepared by:

Terracon Consultants, Inc.

Fort Collins, Colorado

TABLE OF CONTENTS

EXECUTIVE SUMMARY ............................................................................................................ i 1.0 INTRODUCTION .............................................................................................................1 2.0 PROJECT INFORMATION .............................................................................................1

2.1 Project Description ...............................................................................................1 2.2 Site Location and Description...............................................................................2

3.0 SUBSURFACE CONDITIONS ........................................................................................2 3.1 Typical Subsurface Profile ...................................................................................2 3.2 Laboratory Testing ...............................................................................................3 3.3 Corrosion Protection (Water-Soluble Sulfates) .....................................................3 3.4 Groundwater ........................................................................................................3

4.0 RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION ......................................4 4.1 Geotechnical Considerations ...............................................................................4

4.1.1 Expansive Soils ........................................................................................4 4.1.2 Foundation Recommendations .................................................................5

4.2 Earthwork.............................................................................................................5 4.2.1 Site Preparation ........................................................................................5 4.2.2 Demolition ................................................................................................5 4.2.3 Excavation ................................................................................................6 4.2.4 Subgrade Preparation ...............................................................................6 4.2.5 Fill Materials and Placement ......................................................................7 4.2.6 Compaction Requirements ........................................................................8 4.2.7 Utility Trench Backfill ................................................................................9 4.2.8 Grading and Drainage ...............................................................................9

4.3 Foundations .........................................................................................................9 4.3.1 Spread Footings - Design Recommendations .........................................10 4.3.2 Spread Footings - Construction Considerations ......................................11

4.4 Seismic Considerations......................................................................................11 4.5 Floor Systems ....................................................................................................12

4.5.1 Floor System - Design Recommendations ..............................................12 4.5.2 Floor Systems - Construction Considerations .........................................13

4.6 Roadways ..........................................................................................................13 4.6.1 Roadways – Subgrade Preparation and Design .....................................13

5.0 GENERAL COMMENTS ...............................................................................................13

TABLE OF CONTENTS (continued)

Appendix A – FIELD EXPLORATION

Exhibit A-1 Site Location Map

Exhibit A-2 Exploration Plan

Exhibit A-3 Field Exploration Description

Exhibits A-4 to A-16 Boring Logs

Appendix B – LABORATORY TESTING

Exhibit B-1 Laboratory Testing Description

Exhibit B-2 Atterberg Limits Test Results

Exhibits B-3 and B-4 Grain-size Distribution Test Results

Exhibits B-5 and B-6 Swell-consolidation Test Results

Exhibit B-7 Water-Soluble Sulfate Test Results

Appendix C – SUPPORTING DOCUMENTS

Exhibit C-1 General Notes

Exhibit C-2 Unified Soil Classification System

Exhibit C-3 Description of Rock Properties

Exhibit C-4 Laboratory Test Significance and Purpose

Exhibits C-5 and C-6 Report Terminology

Geotechnical Engineering Report South Shore Carter Lake Campground Expansion ■ Larimer County, Colorado July 15, 2016 ■ Terracon Project No. 20165057

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EXECUTIVE SUMMARY

A geotechnical investigation has been performed for the proposed South Shore Carter Lake

Campground expansion to be constructed northwest of CR 31 and Cougar Run Lane in Larimer

County, Colorado. Thirteen (13) borings, presented as Exhibits A-4 through A-16 and designated

as Boring No. 1 through Boring No. 13, were performed to depths of approximately 5 to 15½ feet

below existing site grades. This report specifically addresses the recommendations for the proposed

campground expansion. Borings performed in these areas are for informational purposes and will

be utilized by others.

Based on the information obtained from our subsurface exploration, the site can be developed for

the proposed project. However, the following geotechnical considerations were identified and will

need to be considered:

In general, subsurface conditions encountered in our borings consisted of about 1 to 6 feet

of sand with varying amounts of silt, gravel and cobbles over about 3 to 13½ feet of lean clay

with varying amounts of sand and gravel. Boulders were encountered during completion of

Boring Nos. 1 through 3 at depths of about 5 to 6 feet below existing site grades causing

practical auger refusal. Claystone bedrock was encountered below the lean clay in some of

the borings at depths ranging from about 7 to 14 feet below existing site grades and extended

to maximum depths explored.

Hard to very hard bedrock was encountered at varying depths in several of our borings

completed at this site. Excavation of the upper soils and portions of the comparatively softer

portions of the bedrock can be accomplished with large, conventional excavation equipment.

However, excavation into the very hard bedrock will require efforts including ripping, jack

hammering and possibly drilling and blasting. Our subsurface exploration also indicates

large boulders and bedrock fragments should be expected during excavation on portions of

the site.

The proposed vault toilets and shower buildings may be supported on shallow foundations

bearing on properly prepared on-site soils or on newly placed engineered fill.

A slab-on-grade floor system is recommended for the proposed buildings.

The amount of movement of foundations and floor slabs will be related to the wetting of

underlying supporting soils. Therefore, it is imperative the recommendations discussed in the

4.2.8 Grading and Drainage section of this report be followed to reduce potential movement.

The 2012 International Building Code, Table 1613.5.2 IBC seismic site classification for this

site is C.


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Close monitoring of the construction operations discussed herein will be critical in achieving

the design subgrade support. We therefore recommend that Terracon be retained to

monitor this portion of the work.

This summary should be used in conjunction with the entire report for design purposes. It should

be recognized that details were not included or fully developed in this section, and the report must

be read in its entirety for a comprehensive understanding of the items contained herein. The section

titled GENERAL COMMENTS should be read for an understanding of the report limitations.

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GEOTECHNICAL ENGINEERING REPORT

South Shore Carter Lake Campground Expansion

Northwest of CR 31 and Cougar Run Lane

Larimer County, Colorado Terracon Project No. 20165057

July 15, 2016

1.0 INTRODUCTION

This report presents the results of our geotechnical engineering services performed for the

proposed South Shore Carter Lake Campground expansion to be located northwest of CR 31 and

Cougar Run Lane in Larimer County, Colorado (Exhibit A-1). The purpose of these services is to

provide information and geotechnical engineering recommendations relative to:

subsurface soil and bedrock conditions foundation design and construction

groundwater conditions floor slab design and construction

seismic considerations access road construction

earthwork

excavation considerations

grading and drainage

Our geotechnical engineering scope of work for this project included the initial site visit, the

advancement of thirteen test borings to depths ranging from approximately 5 to 15½ feet below

existing site grades, laboratory testing for soil engineering properties and engineering analyses

to provide excavation, foundation, floor system and roadway design and construction

recommendations.

Logs of the borings along with an Exploration Plan (Exhibit A-2) are included in Appendix A. The

results of the laboratory testing performed on soil and bedrock samples obtained from the site

during the field exploration are included in Appendix B.

2.0 PROJECT INFORMATION

2.1 Project Description

Item Description

Site layout Refer to the Exploration Plan (Exhibit A-2 in Appendix A)

Structures

The proposed construction includes removing and replacing multiple

vault toilets on site, a proposed shower building and additional

campsites with associated access roads and parking areas.

Below-grade areas No below-grades areas planned



Item Description

Traffic loading

Project plans indicate the proposed construction will include new

drive lanes and parking areas for the additional campsites. We

anticipate gravelly-surfacing will be used for the proposed roadways.

2.2 Site Location and Description

Item Description

Location The project site is located northwest of CR 31 and Cougar Run Lane

in Larimer County, Colorado.

Existing site features

The site is currently multiple drive-in campground sites with

associated gravel-surfaced roads, bathrooms, picnic areas and a

sand volleyball court.

Surrounding developments

The site is surrounded by undeveloped land to the east, south and

west and the southern edge of Carter Lake borders the north side of

the site.

Current ground cover

The ground is currently covered with native grasses and weeds,

some native forested areas and some areas of gravel for access

roads around the campsites.

Existing topography

The north side of the site has steep embankments and sits higher

than the rest of the site. The site then slopes gradually down toward

the south and is relatively flat with some rolling hills in the large field

on the southern end of site.

3.0 SUBSURFACE CONDITIONS

3.1 Typical Subsurface Profile

Specific conditions encountered at each boring location are indicated on the individual boring logs

included in Appendix A. Stratification boundaries on the boring logs represent the approximate

location of changes in soil types; in-situ, the transition between materials may be gradual. Based

on the results of the borings, subsurface conditions on the project site can be generalized as

follows:

Material Description Approximate Depth to

Bottom of Stratum Consistency/Density/Hardness

Sand with varying amounts of silt,

gravel and cobbles

About 1 to 6 feet below existing

side grades. Loose to very dense

Lean clay with varying amounts of

sand, gravel and cobbles

About 5 to 15½ feet below

existing site grades. Medium stiff to hard

Boulders Encountered at varying depths

causing practical auger refusal -



Material Description Approximate Depth to

Bottom of Stratum Consistency/Density/Hardness

Claystone bedrock

To the maximum depth of

exploration of about 15 feet.

Only found in Boring Nos. 4, 5,

8, 9, 10, 11, 12 and 13

Hard to very hard

3.2 Laboratory Testing

Representative soil samples were selected for swell-consolidation testing and exhibited no

movement to 2.2 percent swell when wetted. The sands and bedrock are considered low-swelling

to non-expansive. Samples of site soils selected for plasticity testing exhibited low to moderate

plasticity with liquid limits ranging from non-plastic to 42 and plasticity indices ranging from non-

plastic to 24. Laboratory test results are presented in Appendix B.

3.3 Corrosion Protection (Water-Soluble Sulfates)

Results of water-soluble sulfate testing indicate that ASTM Type I or II, V portland cement should

be specified for all project concrete on and below grade. Foundation concrete should be designed

for low sulfate exposure in accordance with the provisions of the ACI Design Manual, Section

318, Chapter 4.

3.4 Groundwater

The boreholes were observed while drilling and after completion for the presence and level of

groundwater. In addition, delayed water levels were also obtained in some borings, using temporary

piezometers. The water levels observed in the boreholes are noted on the attached boring logs, and

are summarized below

Boring Number

Depth to

groundwater while

drilling, ft.

Depth to groundwater

3 days after drilling, ft.

Elevation of

groundwater 3 days

after drilling, ft.

1 Not encountered Backfilled after drilling Backfilled after drilling





6 (temporary piezometer) Not encountered Not encountered Not encountered






Boring Number

Depth to

groundwater while

drilling, ft.

Depth to groundwater

3 days after drilling, ft.

Elevation of

groundwater 3 days

after drilling, ft.

10 (temporary piezometer) Not encountered 6 5806




These observations represent groundwater conditions at the time of the field exploration, and may

not be indicative of other times or at other locations. Groundwater levels can be expected to

fluctuate with varying seasonal and weather conditions, and other factors.

Groundwater level fluctuations occur due to seasonal variations in the water levels present in

Carter Lake, amount of rainfall, runoff and other factors not evident at the time the borings were

performed. Therefore, groundwater levels during construction or at other times in the life of the

structures may be higher or lower than the levels indicated on the boring logs. The possibility of

groundwater level fluctuations should be considered when developing the design and construction

plans for the project.

4.0 RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION

4.1 Geotechnical Considerations

Based on subsurface conditions encountered in the borings, the site appears suitable for the

proposed construction from a geotechnical point of view provided certain precautions and design

and construction recommendations described in this report are followed. We have identified

geotechnical conditions that could impact design and construction of the proposed structures,

access roads, and other campground enhancements.

4.1.1 Expansive Soils

Laboratory testing indicates the native clay soils exhibited low to moderate expansive potential at

the samples in-situ moisture content. However, it is our opinion these materials will exhibit a higher

expansive potential if the clays undergo a significant loss of moisture.

This report provides recommendations to help mitigate the effects of soil shrinkage and

expansion. However, even if these procedures are followed, some movement and cracking in

the structures and flatwork should be anticipated. The severity of cracking and other damage

such as uneven floor slabs will probably increase if any modification of the site results in excessive

wetting or drying of the expansive clays. Eliminating the risk of movement and distress is

generally not feasible, but it may be possible to further reduce the risk of movement if significantly

more expensive measures are used during construction. It is imperative the recommendations

described in section 4.2.8 Grading and Drainage of this report be followed to reduce movement.



4.1.2 Foundation Recommendations

The proposed vault toilets and shower building may be supported on a spread footing foundation

system bearing on properly prepared on-site soils or newly placed engineered fill. We

recommend a slab-on-grade for the interior floor system of the proposed building. Even when

bearing on properly prepared soils, movement of the slab-on-grade floor system is possible

should the subgrade soils undergo an increase in moisture content. We estimate movement of

about 1 inch is possible. If the owner cannot accept the risk of slab movement, a structural floor

should be used.

4.2 Earthwork

The following presents recommendations for site preparation, excavation, subgrade preparation

and placement of engineered fills on the project. All earthwork on the project should be observed

and evaluated by Terracon on a full-time basis. The evaluation of earthwork should include

observation of over-excavation operations, testing of engineered fills, subgrade preparation,

subgrade stabilization, and other geotechnical conditions exposed during the construction of the

project.

4.2.1 Site Preparation

Prior to placing any fill, strip and remove existing vegetation and any other deleterious materials

from the proposed construction areas.

Stripped organic materials should be wasted from the site or used to re-vegetate landscaped areas

or exposed slopes after completion of grading operations. Prior to the placement of fills, the site

should be graded to create a relatively level surface to receive fill, and to provide for a relatively

uniform thickness of fill beneath proposed structures.

If fill is placed in areas of the site where existing slopes are steeper than 5:1 (horizontal:vertical),

the area should be benched to reduce the potential for slippage between existing slopes and fills.

Benches should be wide enough to accommodate compaction and earth moving equipment, and

to allow placement of horizontal lifts of fill.

4.2.2 Demolition

Demolition of the existing vault toilets should include complete removal of all foundation systems,

below-grade structural elements, and exterior flat work within the proposed construction area. This

should include removal of any utilities to be abandoned along with any loose utility trench backfill or

loose backfill found adjacent to existing foundations. All materials derived from the demolition of

existing structures should be removed from the site.

Consideration could be given to re-using the concrete provided the materials are processed and

uniformly blended with the on-site soils. Concrete materials should be processed to a maximum

size of 2-inches and blended at a ratio of 30 percent concrete to 70 percent of on-site soils.



4.2.3 Excavation

Excavation penetrating the upper strata of soils and portions of the comparatively softer bedrock

can be accomplished with large, conventional excavation equipment. Excavation penetrating the

bedrock or cemented soils or soil with large cobbles and boulders may require the use of specialized

heavy-duty equipment, together with ripping or jack-hammering drilling and blasting to advance the

excavation and facilitate rock break-up and removal. Consideration should be given to obtaining a

unit price for difficult excavation in the contract documents for the project.

The soils to be excavated can vary significantly across the site as their classifications are based

solely on the materials encountered in widely-spaced exploratory test borings. The contractor

should verify that similar conditions exist throughout the proposed area of excavation. If different

subsurface conditions are encountered at the time of construction, the actual conditions should be

evaluated to determine any excavation modifications necessary to maintain safe conditions.

Although evidence of fills or underground facilities such as septic tanks and utilities was not

observed during the site reconnaissance, such features could be encountered during construction.

If unexpected fills or underground facilities are encountered, such features should be removed and

the excavation thoroughly cleaned prior to backfill placement and/or construction.

Any over-excavation that extends below the bottom of foundation elevation for the proposed

restroom building should extend laterally beyond all edges of the foundations at least 8 inches per

foot of over-excavation depth below the foundation base elevation. The over-excavation should be

backfilled to the foundation base elevation in accordance with the recommendations presented in

this report.

Depending upon depth of excavation and seasonal conditions, surface water infiltration and/or

groundwater may be encountered in excavations on the site. It is anticipated that pumping from

sumps may be utilized to control water within excavations.

The subgrade soil conditions should be evaluated during the excavation process and the stability

of the soils determined at that time by the contractors’ Competent Person. Slope inclinations flatter

than the OSHA maximum values may have to be used. The individual contractor(s) should be

made responsible for designing and constructing stable, temporary excavations as required to

maintain stability of both the excavation sides and bottom. All excavations should be sloped or

shored in the interest of safety following local, and federal regulations, including current OSHA

excavation and trench safety standards.

As a safety measure, it is recommended that all vehicles and soil piles be kept a minimum lateral

distance from the crest of the slope equal to the slope height. The exposed slope face should be

protected against the elements

4.2.4 Subgrade Preparation

After the vegetative layer has been removed from the construction areas, the top 8 inches of the

exposed ground surface should be scarified, moisture conditioned, and recompacted to at least



95 percent of the maximum dry unit weight as determined by AASHTO T99 before any new fill or

roadway material is placed.

If pockets of soft, loose, or otherwise unsuitable materials are encountered at the bottom of the

foundation excavations and it is inconvenient to lower the foundations, the proposed foundation

elevations may be reestablished by over-excavating the unsuitable soils and backfilling with

compacted engineered fill or lean concrete.

In addition, large cobbles or boulder-sized materials may be encountered beneath foundation

areas. Such conditions could create point loads on the bottom of foundations, increasing the

potential for differential foundation movement. If such conditions are encountered in the

foundation excavations, the cobbles and/or boulders should be removed and be replaced with

engineered fill, conditioned to near optimum moisture content and compacted.

After the bottom of the excavation has been compacted, engineered fill can be placed to bring the

building pad and roadway subgrade to the desired grade. Engineered fill should be placed in

accordance with the recommendations presented in subsequent sections of this report.

The stability of the subgrade may be affected by precipitation, repetitive construction traffic or

other factors. If unstable conditions develop, workability may be improved by scarifying and

drying. Alternatively, over-excavation of wet zones and replacement with granular materials may

be used, or crushed gravel and/or rock can be tracked or “crowded” into the unstable surface soil

until a stable working surface is attained. Lightweight excavation equipment may also be used to

reduce subgrade pumping.

4.2.5 Fill Materials and Placement

The on-site soils or approved granular and low plasticity cohesive imported materials may be used

as fill material. The soil removed from this site that is free of organic or objectionable materials,

as defined by a field technician who is qualified in soil material identification and compaction

procedures, can be re-used as fill for the building pad and roadway subgrade. The bedrock

material excavated from this site may be used as fill materials provided the bedrock is broken

down and processed to meet the criteria of fill materials and compaction provided in this report. It



should be noted that on-site soils and broken down bedrock will require reworking to adjust the

moisture content to meet the compaction criteria.

Imported soils (if required) should meet the following material property requirements:

Gradation Percent finer by weight (ASTM C136)

4” 100

3” 70-100

No. 4 Sieve 50-100

No. 200 Sieve 10-50

Soil Properties Values

Liquid Limit 35 (max.)

Plastic Limit 6 (max.)

Maximum Expansive Potential (%) Non-expansive1

1. Measured on a sample compacted to approximately 95 percent of the maximum dry unit weight as

determined by AASHTO T99 at optimum moisture content. The sample is confined under a 100 psf

surcharge and submerged.

4.2.6 Compaction Requirements

Engineered fill should be placed and compacted in horizontal lifts, using equipment and

procedures that will produce recommended moisture contents and densities throughout the lift.

Item Description

Fill lift thickness 9 inches or less in loose thickness when heavy, self-

propelled compaction equipment is used

Minimum compaction requirements

Fill less than 8 feet in thickness: 95 percent of the

maximum dry unit weight as determined by AASHTO T99

Fill 8 feet or more in thickness: 98 percent of the

maximum dry unit weight as determined by AASHTO T99

Moisture content cohesive soil (clay) -1 to +3 % of the optimum moisture content

Moisture content cohesionless soil

(sand) -3 to 3% of the optimum moisture content



Item Description

1. We recommend engineered fill be tested for moisture content and compaction during placement.

Should the results of the in-place density tests indicate the specified moisture or compaction limits

have not been met, the area represented by the test should be reworked and retested as required

until the specified moisture and compaction requirements are achieved.

2. Specifically, moisture levels should be maintained low enough to allow for satisfactory compaction to

be achieved without the fill material pumping when proofrolled.

3. Moisture conditioned clay materials should not be allowed to dry out. A loss of moisture within these

materials could result in an increase in the material’s expansive potential. Subsequent wetting of

these materials could result in undesirable movement.

4.2.7 Utility Trench Backfill

All trench excavations for the proposed shower building or other areas of the site should be made

with sufficient working space to permit construction including backfill placement and compaction.

All underground piping within or near the proposed structures should be designed with flexible

couplings, so minor deviations in alignment do not result in breakage or distress. Utility knockouts

in foundation walls should be oversized to accommodate differential movements. It is imperative

that utility trenches be properly backfilled with relatively clean materials. If utility trenches are

backfilled with relatively clean granular material, they should be capped with at least 18 inches of

cohesive fill to reduce the infiltration and conveyance of surface water through the trench backfill.

It is strongly recommended that a representative of Terracon provide full-time observation and

compaction testing of trench backfill within building area.

4.2.8 Grading and Drainage

All grades must be adjusted to provide effective drainage away from the proposed building and

existing buildings during construction and maintained throughout the life of the proposed project.

Infiltration of water into foundation excavations must be prevented during construction. Water

permitted to pond near or adjacent to the perimeter of the structures (either during or post-

construction) can result in significantly higher soil movements than those discussed in this report.

As a result, any estimations of potential movement described in this report cannot be relied upon

if positive drainage is not obtained and maintained, and water is allowed to infiltrate the fill and/or

subgrade.

4.3 Foundations

The proposed vault toilet and shower building can be supported by a shallow, spread footing

foundation system. Design recommendations for foundations for the proposed structure and

related structural elements are presented in the following paragraphs.



4.3.1 Spread Footings - Design Recommendations

Description Values

Bearing material Properly prepared on-site soil or new, properly

placed engineered fill.

Maximum allowable bearing pressure 1 On-site lean clay: 2,000 psf

On-site granular soil: 2,500 psf

Lateral earth pressure coefficients 2

On-site lean clay:

Active, Ka = 0.27

Passive, Kp = 3.70

At-rest, Ko = 0.43

On-site granular soil:

Active, Ka = 0.22

Passive, Kp = 4.60

At-rest, Ko = 0.36

Sliding coefficient 2

On-site lean clay:

µ = 0.56


µ = 0.67

Moist soil unit weight

On-site lean clay:

ɣ = 115 pcf


ɣ = 125 pcf

Minimum embedment depth below finished

grade 3 36 inches

Estimated total movement About 1 inch

Estimated differential movement About ½ to ¾ of total movement

1. The recommended maximum allowable bearing pressure assumes any unsuitable fill or soft soils, if

encountered, will be over-excavated and replaced with properly compacted engineered fill. The

design bearing pressure applies to a dead load plus design live load condition. The design bearing

pressure may be increased by one-third when considering total loads that include wind or seismic

conditions.

2. The lateral earth pressure coefficients and sliding coefficients are ultimate values and do not include

a factor of safety. The foundation designer should include the appropriate factors of safety.

3. For frost protection and to reduce the effects of seasonal moisture variations in the subgrade soils.

The minimum embedment depth is for perimeter footings beneath unheated areas and is relative to

lowest adjacent finished grade, typically exterior grade.

Footings should be proportioned to reduce differential foundation movement. As discussed, total

movement resulting from the assumed structural loads is estimated to be on the order of about 1

inch. Additional foundation movements could occur if water from any source infiltrates the



foundation soils; therefore, proper drainage should be provided in the final design and during

construction and throughout the life of the structure. Failure to maintain the proper drainage as

recommended in the 4.2.8 Grading and Drainage section of this report will nullify the movement

estimates provided above.

4.3.2 Spread Footings - Construction Considerations

Spread footing construction should only be considered if the estimated foundation movement can

be tolerated. Subgrade soils beneath footings should be moisture conditioned and compacted as

described in the 4.2 Earthwork section of this report. The moisture content and compaction of

subgrade soils should be maintained until foundation construction.

Footings and foundation walls should be reinforced as necessary to reduce the potential for distress

caused by differential foundation movement.

Unstable subgrade conditions are anticipated as excavations approach the groundwater surface.

Unstable surfaces will need to be stabilized prior to backfilling excavations and/or constructing

the building foundation, floor slab and/or project pavements. The use of angular rock, recycled

concrete and/or gravel pushed or “crowded” into the yielding subgrade is considered suitable

means of stabilizing the subgrade. The use of geogrid materials in conjunction with gravel could

also be considered and could be more cost effective.

Unstable subgrade conditions should be observed by Terracon to assess the subgrade and

provide suitable alternatives for stabilization. Stabilized areas should be proof-rolled prior to

continuing construction to assess the stability of the subgrade.

Foundation excavations should be observed by Terracon. If the soil conditions encountered differ

significantly from those presented in this report, supplemental recommendations will be required.

4.4 Seismic Considerations

Code Used Site Classification

2012 International Building Code (IBC) 1 C 2

1. In general accordance with the 2012 International Building Code, Table 1613.5.2.

2. The 2012 International Building Code (IBC) requires a site soil profile determination extending a

depth of 100 feet for seismic site classification. The current scope requested does not include the

required 100 foot soil profile determination. The borings completed for this project extended to a

maximum depth of about 15½ feet and this seismic site class definition considers that similar soil and

bedrock conditions exist below the maximum depth of the subsurface exploration. Additional

exploration to deeper depths could be performed to confirm the conditions below the current depth of

exploration. Alternatively, a geophysical exploration could be utilized in order to attempt to justify a

more favorable seismic site class. However, we believe a higher seismic site class for this site is

unlikely.



4.5 Floor Systems

A slab-on-grade may be utilized for the interior floor system for the proposed vault toilets and

shower building. If the estimated movement cannot be tolerated, a structurally-supported floor

system, supported independent of the subgrade materials, is recommended.

Subgrade soils beneath interior and exterior slabs should be scarified to a depth of at least 8

inches, moisture conditioned and compacted. The moisture content and compaction of subgrade

soils should be maintained until slab construction.

4.5.1 Floor System - Design Recommendations

Even when bearing on properly prepared soils, movement of the slab-on-grade floor system is

possible should the subgrade soils undergo an increase in moisture content. We estimate

movement of about 1 inch is possible.

For structural design of concrete slabs-on-grade subjected to point loadings, a modulus of

subgrade reaction of 100 pounds per cubic inch (pci) may be used for floors supported on re-

compacted existing soils at the site. A modulus of 200 pci may be used for floors supported on

at least 1 foot of non-expansive, imported granular fill.

Additional floor slab design and construction recommendations are as follows:

Positive separations and/or isolation joints should be provided between slabs and all

foundations, columns, or utility lines to allow independent movement.

Control joints should be saw-cut in slabs in accordance with ACI Design Manual, Section

302.1R-37 8.3.12 (tooled control joints are not recommended) to control the location and

extent of cracking.

Interior utility trench backfill placed beneath slabs should be compacted in accordance

with the recommendations presented in the 4.2 Earthwork section of this report.

Floor slabs should not be constructed on frozen subgrade.

The use of a vapor retarder should be considered beneath concrete slabs that will be

covered with wood, tile, carpet or other moisture sensitive or impervious floor coverings,

or when the slab will support equipment sensitive to moisture. When conditions warrant

the use of a vapor retarder, the slab designer and slab contractor should refer to ACI

302 for procedures and cautions regarding the use and placement of a vapor retarder.

Other design and construction considerations, as outlined in the ACI Design Manual,

Section 302.1R are recommended.



4.5.2 Floor Systems - Construction Considerations

Movements of slabs-on-grade using the recommendations discussed in previous sections of this

report will likely be reduced and tend to be more uniform. The estimates discussed above assume

that the other recommendations in this report are followed. Additional movement could occur

should the subsurface soils become wetted to significant depths, which could result in potential

excessive movement causing uneven floor slabs and severe cracking. This could be due to over

watering of landscaping, poor drainage, improperly functioning drain systems, and/or broken utility

lines. Therefore, it is imperative that the recommendations presented in this report be followed.

4.6 Roadways

4.6.1 Roadways – Subgrade Preparation and Design

On most project sites, the site grading is accomplished relatively early in the construction phase.

Fills are typically placed and compacted in a uniform manner. However as construction proceeds,

the subgrade may be disturbed due to utility excavations, construction traffic, desiccation, or

rainfall/snow melt. As a result, the roadway subgrade may not be suitable for construction and

corrective action will be required. The subgrade should be carefully evaluated at the time of

roadway construction for signs of disturbance or instability. We recommend the roadway

subgrades be thoroughly proofrolled with a loaded tandem-axle dump truck prior to final grading

and placement of gravel-surfacing materials. All roadway areas should be moisture conditioned

and properly compacted to the recommendations in this report immediately prior to surfacing.

5.0 GENERAL COMMENTS

Terracon should be retained to review the final design plans and specifications so comments can

be made regarding interpretation and implementation of our geotechnical recommendations in

the design and specifications. Terracon also should be retained to provide observation and testing

services during grading, excavation, foundation construction and other earth-related construction

phases of the project.

The analysis and recommendations presented in this report are based upon the data obtained

from the borings performed at the indicated locations and from other information discussed in this

report. This report does not reflect variations that may occur between borings, across the site, or

due to the modifying effects of construction or weather. The nature and extent of such variations

may not become evident until during or after construction. If variations appear, we should be

immediately notified so that further evaluation and supplemental recommendations can be

provided.

The scope of services for this project does not include either specifically or by implication any

environmental or biological (e.g., mold, fungi, and bacteria) assessment of the site or identification

or prevention of pollutants, hazardous materials or conditions. If the owner is concerned about

the potential for such contamination or pollution, other studies should be undertaken.



This report has been prepared for the exclusive use of our client for specific application to the

project discussed and has been prepared in accordance with generally accepted geotechnical

engineering practices. No warranties, either express or implied, are intended or made. Site

safety, excavation support, and dewatering requirements are the responsibility of others. In the

event that changes in the nature, design, or location of the project as described in this report are

planned, the conclusions and recommendations contained in this report shall not be considered

valid unless Terracon reviews the changes and either verifies or modifies the conclusions of this

report in writing.

APPENDIX A

FIELD EXPLORATION

SITE LOCATION MAP

South Shore Carter Lake Campground Expansion (LC #5022)

Northwest of CR 31 and Cougar Run Lane, Larimer County, CO

TOPOGRAPHIC MAP IMAGE COURTESY OF THE U.S. GEOLOGICAL SURVEY QUADRANGLES INCLUDE: CARTER LAKE RESERVOIR, CO (1971).

1901 Sharp Point Dr Ste C

Fort Collins, CO 80525-4429

20165057

Project Manager:

Drawn by: Checked by:

Approved by:

MGH

EDB

EDB

1”=2,000’

7/7/2016

Project No.

Scale: File Name:

Date: A-1

Exhibit EDB

SITE

EXPLORATION PLAN

South Shore Carter Lake Campground Expansion (LC #5022)

Northwest of CR 31 and Cougar Run Lane, Larimer County, CO

1901 Sharp Point Dr Ste C

Fort Collins, CO 80525-4429

DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS NOT INTENDED FOR CONSTRUCTION PURPOSES

20165057

AERIAL PHOTOGRAPHY PROVIDED BY MICROSOFT BING MAPS

MGH

EDB

EDB

AS SHOWN

7/7/2016

Scale:

A-2

Exhibit Project Manager:

Drawn by:

Checked by:

Approved by:

Project No.

File Name:

Date:

EDB


Responsive ■ Resourceful ■ Reliable Exhibit A-3

Field Exploration Description

The locations of borings were selected by the client based upon the proposed development shown

on the provided site plan. The borings were located in the field by measuring from existing site

features and using a hand-held GPS unit. The ground surface elevation was estimated using

topographic maps of the area.

The borings were drilled with a CME-550 buggy-mounted rotary drill rig with solid-stem augers.

During the drilling operations, lithologic logs of the borings were recorded by the field engineer.

Disturbed samples were obtained at selected intervals utilizing a 2-inch outside diameter split-

spoon sampler and a 3-inch outside diameter ring-barrel sampler. Disturbed bulk samples were

obtained from auger cuttings. Penetration resistance values were recorded in a manner similar to

the standard penetration test (SPT). This test consists of driving the sampler into the ground with

a 140-pound hammer free-falling through a distance of 30 inches. The number of blows required

to advance the ring-barrel sampler 12 inches (18 inches for standard split-spoon samplers, final

12 inches are recorded) or the interval indicated, is recorded as a standard penetration resistance

value (N-value). The blow count values are indicated on the boring logs at the respective sample

depths. Ring-barrel sample blow counts are not considered N-values.

A CME automatic SPT hammer was used to advance the samplers in the borings performed on this

site. A greater efficiency is typically achieved with the automatic hammer compared to the

conventional safety hammer operated with a cathead and rope. Published correlations between the

SPT values and soil properties are based on the lower efficiency cathead and rope method. This

higher efficiency affects the standard penetration resistance blow count value by increasing the

penetration per hammer blow over what would be obtained using the cathead and rope method. The

effect of the automatic hammer's efficiency has been considered in the interpretation and analysis of

the subsurface information for this report.

The standard penetration test provides a reasonable indication of the in-place density of sandy

type materials, but only provides an indication of the relative stiffness of cohesive materials since

the blow count in these soils may be affected by the moisture content of the soil. In addition,

considerable care should be exercised in interpreting the N-values in gravelly soils, particularly

where the size of the gravel particle exceeds the inside diameter of the sampler.

Groundwater measurements were obtained in the borings at the time of site exploration,

temporary piezometers were installed in four of the borings across the site, borings that did not

have a temporary piezometer installed were backfilled with auger cutters and sand (if needed)

immediately after completion of drilling. Groundwater levels were checked in the borings with

piezometers several days after drilling. After subsequent groundwater measurements were

obtained, the temporary piezometers were removed and the borings were backfilled with auger

cuttings and sand (if needed). Some settlement of the backfill may occur and should be repaired

as soon as possible.

27

8

5 NP

5785.5

5781

9-8-50/5"N=59/11"

12-39

0.5

5.0

VEGETATIVE LAYER - 6 inchesSILTY SAND (SM), with varying amounts of gravel, cobblesand some boulders, brown to orange-brown, dense to verydense

Auger refusal due to apparent boulders at 5 feet

Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.

GR

APH

ICLO

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THIS

BOR

ING

LOG

ISN

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RAT

EDFR

OM

OR

IGIN

ALR

EPO

RT.

GEO

SMAR

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.GPJ

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Northeast of CR 31 and Cougar Run Lane Larimer County, ColoradoSITE:

Page 1 of 1

Advancement Method:4-inch solid-stem auger

Abandonment Method:Boring backfilled with soil cuttings upon completion.

1901 Sharp Point Dr Ste CFort Collins, CO

Notes:

Project No.: 20165057

Drill Rig: CME-550

Boring Started: 6/28/2016

BORING LOG NO. 1Larimer County ColoradoCLIENT:Fort Collins, Colorado

Driller: Terracon Consulting, Inc.

Boring Completed: 6/28/2016

Exhibit: A-4

See Exhibit A-3 for description of field procedures.

See Appendix B for description of laboratoryprocedures and additional data (if any).See Appendix C for explanation of symbols andabbreviations.

PROJECT: South Shore Carter Lake CampgroundExpansion

PER

CEN

TFI

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WAT

ERC

ON

TEN

T(%

)

DR

YU

NIT

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GH

T(p

cf)

ATTERBERGLIMITS

LL-PL-PISurface Elev.: 5786 (Ft.)

ELEVATION (Ft.) SAM

PLE

TYPE

WAT

ERLE

VEL

OBS

ERVA

TIO

NS

DEP

TH(F

t.)

5

SWEL

L-C

ON

SOL

/LO

AD(%

/psf

)

FIEL

DTE

STR

ESU

LTS

DEPTH

LOCATION See Exhibit A-2

Latitude: 40.31495° Longitude: -105.22382°

No free water observedWATER LEVEL OBSERVATIONS

7

5783.5

5782

5778

10-9-25N=34

0.5

2.0

6.0

VEGETATIVE LAYER - 6 inchesSILTY SAND, with gravel, cobbles and some boulders, darkbrown to brown, dense

POORLY GRADED GRAVEL WITH SILT AND SAND, withvarying amounts of cobbles and boulders, orange-brown tobrown, dense



GR

APH

ICLO

G

THIS

BOR

ING

LOG

ISN

OT

VALI

DIF

SEPA

RAT

EDFR

OM

OR

IGIN

ALR

EPO

RT.

GEO

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6


Page 1 of 1




Notes:


Drill Rig: CME-550





Exhibit: A-5




PER

CEN

TFI

NES

WAT

ERC

ON

TEN

T(%

)

DR

YU

NIT

WEI

GH

T(p

cf)

ATTERBERGLIMITS


ELEVATION (Ft.) SAM

PLE

TYPE

WAT

ERLE

VEL

OBS

ERVA

TIO

NS

DEP

TH(F

t.)

5

SWEL

L-C

ON

SOL

/LO

AD(%

/psf

)

FIEL

DTE

STR

ESU

LTS

DEPTH




18

19

5782.5

5781

5778

2-3-8N=11

0.5

2.0

5.0

VEGETATIVE LAYER - 6 inchesSILTY SAND, with gravel, cobbles and some boulders, darkbrown to brown, dense

SANDY LEAN CLAY, with varying amounts of gravel, cobblesand some boulders, orange-brown, stiff



GR

APH

ICLO

G

THIS

BOR

ING

LOG

ISN

OT

VALI

DIF

SEPA

RAT

EDFR

OM

OR

IGIN

ALR

EPO

RT.

GEO

SMAR

TLO

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2016

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Page 1 of 1




Notes:


Drill Rig: CME-550





Exhibit: A-6




PER

CEN

TFI

NES

WAT

ERC

ON

TEN

T(%

)

DR

YU

NIT

WEI

GH

T(p

cf)

ATTERBERGLIMITS


ELEVATION (Ft.) SAM

PLE

TYPE

WAT

ERLE

VEL

OBS

ERVA

TIO

NS

DEP

TH(F

t.)

5

SWEL

L-C

ON

SOL

/LO

AD(%

/psf

)

FIEL

DTE

STR

ESU

LTS

DEPTH




12

14

15

13

14

116 NP

5772.5

5768

5760

5758.5

4-4-4N=8

10-19

28-19-14N=33

50/3"N=50/3"

0.5

5.0

13.0

14.3

VEGETATIVE LAYER - 6 inchesPOORLY GRADED GRAVEL WITH SILT AND SAND(GP-GM), dark brown to brown, loose to medium dense

LEAN CLAY WITH SAND, with gravel, reddish-brown tobrown, stiff

SEDIMENTARY BEDROCK - CLAYSTONE, reddish-brown,very hard

Boring Terminated at 14.3 Feet


GR

APH

ICLO

G

THIS

BOR

ING

LOG

ISN

OT

VALI

DIF

SEPA

RAT

EDFR

OM

OR

IGIN

ALR

EPO

RT.

GEO

SMAR

TLO

G-N

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2016

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.GPJ

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6


Page 1 of 1




Notes:


Drill Rig: CME-550





Exhibit: A-7




PER

CEN

TFI

NES

WAT

ERC

ON

TEN

T(%

)

DR

YU

NIT

WEI

GH

T(p

cf)

ATTERBERGLIMITS


ELEVATION (Ft.) SAM

PLE

TYPE

WAT

ERLE

VEL

OBS

ERVA

TIO

NS

DEP

TH(F

t.)

5

10

SWEL

L-C

ON

SOL

/LO

AD(%

/psf

)

FIEL

DTE

STR

ESU

LTS

DEPTH




6416

16

10

8

115

38-20-18

5787.5

5781

5775

5773

0.0/1000

3-5-6N=11

3-5-5N=10

4-7

22-50/5"N=72/11"

0.5

7.0

13.0

14.9

VEGETATIVE LAYER - 6 inchesSANDY LEAN CLAY, with gravel, dark brown to brown, stiff

LEAN CLAY WITH SAND, with gravel, orange-brown toreddish-brown, stiff to very hard




GR

APH

ICLO

G

THIS

BOR

ING

LOG

ISN

OT

VALI

DIF

SEPA

RAT

EDFR

OM

OR

IGIN

ALR

EPO

RT.

GEO

SMAR

TLO

G-N

OW

ELL

2016

5057

.GPJ

TER

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2015

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Page 1 of 1




Notes:


Drill Rig: CME-550





Exhibit: A-8




PER

CEN

TFI

NES

WAT

ERC

ON

TEN

T(%

)

DR

YU

NIT

WEI

GH

T(p

cf)

ATTERBERGLIMITS


ELEVATION (Ft.) SAM

PLE

TYPE

WAT

ERLE

VEL

OBS

ERVA

TIO

NS

DEP

TH(F

t.)

5

10

SWEL

L-C

ON

SOL

/LO

AD(%

/psf

)

FIEL

DTE

STR

ESU

LTS

DEPTH




33

7

10

10

12

113 34-19-15

5775.5

5770

5760.5

+2.2/500

6-9-9N=18

16-20

7-11-8N=19

6-6-8N=14

0.5

6.0

15.5

VEGETATIVE LAYER - 6 inchesCLAYEY SAND (SC), with gravel, dark brown to brown,medium dense

LEAN CLAY WITH SAND, with gravel, reddish-brown toorange-brown, very stiff



GR

APH

ICLO

G

THIS

BOR

ING

LOG

ISN

OT

VALI

DIF

SEPA

RAT

EDFR

OM

OR

IGIN

ALR

EPO

RT.

GEO

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TLO

G-N

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2016

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Page 1 of 1




Notes:


Drill Rig: CME-550





Exhibit: A-9




PER

CEN

TFI

NES

WAT

ERC

ON

TEN

T(%

)

DR

YU

NIT

WEI

GH

T(p

cf)

ATTERBERGLIMITS


ELEVATION (Ft.) SAM

PLE

TYPE

WAT

ERLE

VEL

OBS

ERVA

TIO

NS

DEP

TH(F

t.)

5

10

15

SWEL

L-C

ON

SOL

/LO

AD(%

/psf

)

FIEL

DTE

STR

ESU

LTS

DEPTH



Temporary piezometer installedNo free water observed

WATER LEVEL OBSERVATIONS

38

1

3

7

NP

5774.5

5773

5770

5762

Sample takenfrom auger

cuttings due tocaving of sands,

gravel andcobbles



gravel andcobbles



gravel andcobbles

0.5

2.0

5.0

13.0

VEGETATIVE LAYER - 6 inchesSILTY SAND, with gravel, dark brown to brown, dense

SILTY CLAYEY SAND WITH GRAVEL (SM), white to pink,very hard, dense

LEAN CLAY WITH SAND, with varying amounts of gravel,cobbles and boulders, reddish-brown to orange-brown, stiff



GR

APH

ICLO

G

THIS

BOR

ING

LOG

ISN

OT

VALI

DIF

SEPA

RAT

EDFR

OM

OR

IGIN

ALR

EPO

RT.

GEO

SMAR

TLO

G-N

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ELL

2016

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.GPJ

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Page 1 of 1




Notes:


Drill Rig: CME-550





Exhibit: A-10




PER

CEN

TFI

NES

WAT

ERC

ON

TEN

T(%

)

DR

YU

NIT

WEI

GH

T(p

cf)

ATTERBERGLIMITS


ELEVATION (Ft.) SAM

PLE

TYPE

WAT

ERLE

VEL

OBS

ERVA

TIO

NS

DEP

TH(F

t.)

5

10

SWEL

L-C

ON

SOL

/LO

AD(%

/psf

)

FIEL

DTE

STR

ESU

LTS

DEPTH




19

12

8

7

105

5800.5

5800

5794

5786.5

13-20

13-16-20N=36

50/3"N=50/3"

50/4"N=50/4"

0.5

1.0

7.0

14.3

VEGETATIVE LAYER - 6 inchesSILTY SAND, with gravel, dark brown to brownSANDY LEAN CLAY, with gravel, orange-brown toreddish-brown, hard

SEDIMENTARY BEDROCK - CLAYSTONE, orange-brown toreddish-brown, very hard



GR

APH

ICLO

G

THIS

BOR

ING

LOG

ISN

OT

VALI

DIF

SEPA

RAT

EDFR

OM

OR

IGIN

ALR

EPO

RT.

GEO

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2016

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Page 1 of 1




Notes:


Drill Rig: CME-550





Exhibit: A-11




PER

CEN

TFI

NES

WAT

ERC

ON

TEN

T(%

)

DR

YU

NIT

WEI

GH

T(p

cf)

ATTERBERGLIMITS


ELEVATION (Ft.) SAM

PLE

TYPE

WAT

ERLE

VEL

OBS

ERVA

TIO

NS

DEP

TH(F

t.)

5

10

SWEL

L-C

ON

SOL

/LO

AD(%

/psf

)

FIEL

DTE

STR

ESU

LTS

DEPTH





74

7

3

9

10

114

28-18-10

5804.5

5803.5

5792

5789.5

35-25-20N=45

19-32

6-17-19N=36

39-40-42N=82

0.5

1.5

13.0

15.5

VEGETATIVE LAYER - 6 inchesSANDY LEAN CLAY, with gravel, dark brown to brown

LEAN CLAY WITH SAND (CL), with gravel, orange-brown toreddish-brown, hard




GR

APH

ICLO

G

THIS

BOR

ING

LOG

ISN

OT

VALI

DIF

SEPA

RAT

EDFR

OM

OR

IGIN

ALR

EPO

RT.

GEO

SMAR

TLO

G-N

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ELL

2016

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Page 1 of 1




Notes:


Drill Rig: CME-550





Exhibit: A-12




PER

CEN

TFI

NES

WAT

ERC

ON

TEN

T(%

)

DR

YU

NIT

WEI

GH

T(p

cf)

ATTERBERGLIMITS


ELEVATION (Ft.) SAM

PLE

TYPE

WAT

ERLE

VEL

OBS

ERVA

TIO

NS

DEP

TH(F

t.)

5

10

15

SWEL

L-C

ON

SOL

/LO

AD(%

/psf

)

FIEL

DTE

STR

ESU

LTS

DEPTH




6618

16

18

10

114

39-20-19

5811.5

5805

5800

5797.5

3-5-6N=11

4-3-5N=8

15-23

50/5"N=50/5"

0.5

7.0

12.0

14.4

VEGETATIVE LAYER - 6 inchesSANDY LEAN CLAY (CL), with gravel, dark brown to brown,stiff

LEAN CLAY WITH SAND, with gravel, orange-brown toreddish-brown, very stiff




GR

APH

ICLO

G

THIS

BOR

ING

LOG

ISN

OT

VALI

DIF

SEPA

RAT

EDFR

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OR

IGIN

ALR

EPO

RT.

GEO

SMAR

TLO

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ELL

2016

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Page 1 of 1




Notes:


Drill Rig: CME-550





Exhibit: A-13




PER

CEN

TFI

NES

WAT

ERC

ON

TEN

T(%

)

DR

YU

NIT

WEI

GH

T(p

cf)

ATTERBERGLIMITS


ELEVATION (Ft.) SAM

PLE

TYPE

WAT

ERLE

VEL

OBS

ERVA

TIO

NS

DEP

TH(F

t.)

5

10

SWEL

L-C

ON

SOL

/LO

AD(%

/psf

)

FIEL

DTE

STR

ESU

LTS

DEPTH



Temporary piezometer installed6' in temporary piezometer on 7/1/2016


16

12

7

9

117

5806.5

5801

5799

5793

6-9

6-9-12N=21

50/6"N=50/6"

50/2"N=50/2"

0.5

6.0

8.0

14.2

VEGETATIVE LAYER - 6 inchesSANDY LEAN CLAY, with gravel, dark brown to brown, stiff tovery stiff

LEAN CLAY WITH SAND, with gravel, orange-brown toreddish-brown, stiff

SEDIMENTARY BEDROCK - CLAYSTONE, orange-brown toreddish-brown, very hard



GR

APH

ICLO

G

THIS

BOR

ING

LOG

ISN

OT

VALI

DIF

SEPA

RAT

EDFR

OM

OR

IGIN

ALR

EPO

RT.

GEO

SMAR

TLO

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ELL

2016

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Page 1 of 1




Notes:


Drill Rig: CME-550





Exhibit: A-14




PER

CEN

TFI

NES

WAT

ERC

ON

TEN

T(%

)

DR

YU

NIT

WEI

GH

T(p

cf)

ATTERBERGLIMITS


ELEVATION (Ft.) SAM

PLE

TYPE

WAT

ERLE

VEL

OBS

ERVA

TIO

NS

DEP

TH(F

t.)

5

10

SWEL

L-C

ON

SOL

/LO

AD(%

/psf

)

FIEL

DTE

STR

ESU

LTS

DEPTH




618

10

10

8

113

42-18-24

5804.5

5798

5791

5790.5

13-13-12N=25

6-9-10N=19

17-17

50/5"N=50/5"

0.5

7.0

13.9

14.4

VEGETATIVE LAYER - 6 inchesSANDY LEAN CLAY (CL), with gravel, dark brown to brown,very stiff

LEAN CLAY WITH SAND, with gravel, orange-brown toreddish-brown, very stiff

SEDIMENTARY BEDROCK - CLAYSTONE, reddish-brown,very hardBoring Terminated at 14.4 Feet


GR

APH

ICLO

G

THIS

BOR

ING

LOG

ISN

OT

VALI

DIF

SEPA

RAT

EDFR

OM

OR

IGIN

ALR

EPO

RT.

GEO

SMAR

TLO

G-N

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ELL

2016

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Page 1 of 1




Notes:


Drill Rig: CME-550





Exhibit: A-15




PER

CEN

TFI

NES

WAT

ERC

ON

TEN

T(%

)

DR

YU

NIT

WEI

GH

T(p

cf)

ATTERBERGLIMITS


ELEVATION (Ft.) SAM

PLE

TYPE

WAT

ERLE

VEL

OBS

ERVA

TIO

NS

DEP

TH(F

t.)

5

10

SWEL

L-C

ON

SOL

/LO

AD(%

/psf

)

FIEL

DTE

STR

ESU

LTS

DEPTH




52

7

10

8

8

136 26-17-9

5789.5

5786.5

5779.5

5775

5-7-6N=13

10-16

20-15-15N=30

25-50/5"N=75/11"

0.5

3.5

10.5

14.9

VEGETATIVE LAYER - 6 inchesSILTY SAND, with gravel, dark brown to brown, mediumdense

SANDY LEAN CLAY (CL), with gravel, orange-brown toreddish-brown, very stiff

SEDIMENTARY BEDROCK - CLAYSTONE, reddish-brown,hard to very hard



GR

APH

ICLO

G

THIS

BOR

ING

LOG

ISN

OT

VALI

DIF

SEPA

RAT

EDFR

OM

OR

IGIN

ALR

EPO

RT.

GEO

SMAR

TLO

G-N

OW

ELL

2016

5057

.GPJ

TER

RAC

ON

2015

.GD

T7/

15/1

6


Page 1 of 1




Notes:


Drill Rig: CME-550





Exhibit: A-16




PER

CEN

TFI

NES

WAT

ERC

ON

TEN

T(%

)

DR

YU

NIT

WEI

GH

T(p

cf)

ATTERBERGLIMITS


ELEVATION (Ft.) SAM

PLE

TYPE

WAT

ERLE

VEL

OBS

ERVA

TIO

NS

DEP

TH(F

t.)

5

10

SWEL

L-C

ON

SOL

/LO

AD(%

/psf

)

FIEL

DTE

STR

ESU

LTS

DEPTH





APPENDIX B

LABORATORY TESTING


Responsive ■ Resourceful ■ Reliable Exhibit B-1

Laboratory Testing Description

The soil and bedrock samples retrieved during the field exploration were returned to the laboratory

for observation by the project geotechnical engineer. At that time, the field descriptions were

reviewed and an applicable laboratory testing program was formulated to determine engineering

properties of the subsurface materials.

Laboratory tests were conducted on selected soil and bedrock samples. The results of these

tests are presented on the boring logs and in this appendix. The test results were used for the

geotechnical engineering analyses, and the development of foundation and earthwork

recommendations. The laboratory tests were performed in general accordance with applicable

locally accepted standards. Soil samples were classified in general accordance with the Unified

Soil Classification System described in Appendix C. Rock samples were visually classified in

general accordance with the description of rock properties presented in Appendix C. Procedural

standards noted in this report are for reference to methodology in general. In some cases variations

to methods are applied as a result of local practice or professional judgment.

Water content Plasticity index

Grain-size distribution

Consolidation/swell

Dry density

Water-soluble sulfate content

0

10

20

30

40

50

60

0 20 40 60 80 100

CHor

OH

CLor

OL

ML or OL

MH or OH

PL PIBoring ID Depth Description

SILTY SAND

POORLY GRADED GRAVEL with SILT and SAND

SANDY LEAN CLAY

CLAYEY SAND

SILTY SAND with GRAVEL

LEAN CLAY with SAND

SANDY LEAN CLAY

SANDY LEAN CLAY

SANDY LEAN CLAY

SMGP-GM

CLSCSMCLCLCLCL

Fines

PLASTICITY

INDEX

LIQUID LIMIT

"U" Lin

e

"A" Line

NPNP38342328394226

NPNP20192318201817

NPNP1815NP1019249

271264333874666152

LL USCS

145679101213

ATTERBERG LIMITS RESULTSASTM D4318

4 - 54 - 5

2 - 3.54 - 5

49 - 10.52 - 3.52 - 3.5

4 - 5

PROJECT NUMBER: 20165057PROJECT: South Shore Carter Lake

Campground Expansion

SITE: Northeast of CR 31 and Cougar Run Lane Larimer County, Colorado

CLIENT: Larimer County Colorado Fort Collins, Colorado

EXHIBIT: B-21901 Sharp Point Dr Ste C

Fort Collins, CO

LABO

RAT

OR

YTE

STS

ARE

NO

TVA

LID

IFSE

PAR

ATED

FRO

MO

RIG

INAL

REP

OR

T.AT

TER

BER

GLI

MIT

S20

1650

57.G

PJTE

RR

ACO

N20

15.G

DT

7/7/

16

CL-ML

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

0.0010.010.1110100

1

4

5

6

7

NP

NP

38

34

23

0.088

0.288

0.209

15.623

0.194

1.271

9.5

19

4.75

4.75

12.5

6 16 20 30 40 501.5 2006 810

6.3

18.3

0.0

0.0

23.1

14

27.1

11.7

63.8

32.6

38.1

%Fines

LL PL PI

41 3/4 1/2 60

fine

1

4

5

6

7

265.42

GRAIN SIZE IN MILLIMETERS

PER

CEN

TFI

NER

BYW

EIG

HT

coarse fine

HYDROMETERU.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS

NP

NP

20

19

23

NP

NP

18

15

NP

0.09

D100

Cc Cu

SILT OR CLAY

4

%Sand%GravelD30 D10

4 - 5

4 - 5

2 - 3.5

4 - 5

4

3/8 3 100 1403 2

COBBLES GRAVEL SAND

USCS Classification

66.6

34.2

35.5

64.8

37.4

D60

coarse medium

Boring ID Depth

Boring ID Depth

GRAIN SIZE DISTRIBUTION

4 - 5

4 - 5

2 - 3.5

4 - 5

4

SILTY SAND (SM)

POORLY GRADED GRAVEL with SILT and SAND (GP-GM)

SANDY LEAN CLAY (CL)

CLAYEY SAND (SC)

SILTY SAND with GRAVEL (SM)

ASTM D422 / ASTM C136






Fort Collins, CO

LABO

RAT

OR

YTE

STS

ARE

NO

TVA

LID

IFSE

PAR

ATED

FRO

MO

RIG

INAL

REP

OR

T.G

RAI

NSI

ZE:U

SCS-

220

1650

57.G

PJ35

1590

97-A

TTER

BER

GIS

SUE.

GPJ

7/7/

16

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

0.0010.010.1110100

9

10

12

13

28

39

42

26

0.118

4.75

2

12.5

9.5

6 16 20 30 40 501.5 2006 810

0.0

0.0

0.2

3.7

14

74.2

66.3

60.9

52.1

%Fines

LL PL PI

41 3/4 1/2 60

fine

9

10

12

13

GRAIN SIZE IN MILLIMETERS

PER

CEN

TFI

NER

BYW

EIG

HT

coarse fine

HYDROMETERU.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS

18

20

18

17

10

19

24

9

D100

Cc Cu

SILT OR CLAY

4

%Sand%GravelD30 D10

9 - 10.5

2 - 3.5

2 - 3.5

4 - 5

3/8 3 100 1403 2

COBBLES GRAVEL SAND

USCS Classification

19.6

33.5

32.2

42.8

D60

coarse medium

Boring ID Depth

Boring ID Depth

GRAIN SIZE DISTRIBUTION

9 - 10.5

2 - 3.5

2 - 3.5

4 - 5

LEAN CLAY with SAND (CL)




ASTM D422 / ASTM C136






Fort Collins, CO

LABO

RAT

OR

YTE

STS

ARE

NO

TVA

LID

IFSE

PAR

ATED

FRO

MO

RIG

INAL

REP

OR

T.G

RAI

NSI

ZE:U

SCS-

220

1650

57.G

PJ35

1590

97-A

TTER

BER

GIS

SUE.

GPJ

7/7/

16

-6

-4

-2

0

2

4

6

8

10

100 1,000 10,000

AXIA

LST

RAI

N,%

PRESSURE, psf

SWELL CONSOLIDATION TESTASTM D4546

NOTES: The sample exhibited no movement upon wetting under an applied pressure of 1,000 psf.

Specimen Identification Classification , pcf

1155 10

WC, %

9 - 10 ft






Fort Collins, CO

LABO

RAT

OR

YTE

STS

ARE

NO

TVA

LID

IFSE

PAR

ATED

FRO

MO

RIG

INAL

REP

OR

T.TC

_CO

NSO

L_ST

RAI

N-U

SCS

2016

5057

.GPJ

TER

RAC

ON

2012

.GD

T7/

7/16

mghayes

Typewriter

LEAN CLAY WITH SAND

-6

-4

-2

0

2

4

6

8

10

100 1,000 10,000

AXIA

LST

RAI

N,%

PRESSURE, psf

SWELL CONSOLIDATION TESTASTM D4546

NOTES: The sample exhibited 2.2 percent sweel upon wetting under an applied pressure of 500 psf.

Specimen Identification Classification , pcf

1126 10

WC, %

CLAYEY SAND(SC)4 - 5 ft






Fort Collins, CO

LABO

RAT

OR

YTE

STS

ARE

NO

TVA

LID

IFSE

PAR

ATED

FRO

MO

RIG

INAL

REP

OR

T.TC

_CO

NSO

L_ST

RAI

N-U

SCS

2016

5057

.GPJ

TER

RAC

ON

2012

.GD

T7/

7/16

160708055TASK NO:

Analytical Results

Terracon, Inc. - Fort CollinsEric D. Bernhardt

Company:Report To:

Company:Bill To:

1901 Sharp Point DriveSuite CFort Collins CO 80525

Accounts PayableTerracon, Inc. - A/P18001 W. 106th StSuite 300Olathe KS 66061

South Shore Carter Lake 20165057Date Reported: 7/15/16

Task No.: 160708055

Matrix: Soil - Geotech

Date Received: 7/8/16

Client Project:Client PO:

3 @ 4Customer Sample ID

Test Method

160708055-01Lab Number:

ResultSulfate - Water Soluble AASHTO T290-91/ ASTM D4327 0.006 %


Test Method

160708055-02Lab Number:



Test Method

160708055-03Lab Number:


240 South Main Street / Brighton, CO 80601-0507 / 303-659-2313Mailing Address: P.O. Box 507 / Brighton, CO 80601-0507 / Fax: 303-659-2315

DATA APPROVED FOR RELEASE BY

Abbreviations/ References:

160708055

AASHTO - American Association of State Highway and Transportation Officials. ASTM - American Society for Testing and Materials. ASA - American Society of Agronomy. DIPRA - Ductile Iron Pipe Research Association Handbook of Ductile Iron Pipe.

mghayes

Typewriter

EXHIBIT: B-7

mghayes

Typewriter

APPENDIX C

SUPPORTING DOCUMENTS

Exhibit: C-1

Unconfined Compressive StrengthQu, (psf)

500 to 1,000

2,000 to 4,000

4,000 to 8,000

1,000 to 2,000

less than 500

> 8,000

Non-plasticLowMediumHigh

DESCRIPTION OF SYMBOLS AND ABBREVIATIONSSA

MPL

ING

WAT

ERLE

VEL

FIEL

DTE

STS

GENERAL NOTES

Over 12 in. (300 mm)12 in. to 3 in. (300mm to 75mm)3 in. to #4 sieve (75mm to 4.75 mm)#4 to #200 sieve (4.75mm to 0.075mmPassing #200 sieve (0.075mm)

Particle Size

< 55 - 12> 12

Percent ofDry Weight

Descriptive Term(s)of other constituents

RELATIVE PROPORTIONS OF FINES

01 - 1011 - 30

> 30

Plasticity Index

Soil classification is based on the Unified Soil Classification System. Coarse Grained Soils have more than 50% of their dryweight retained on a #200 sieve; their principal descriptors are: boulders, cobbles, gravel or sand. Fine Grained Soils haveless than 50% of their dry weight retained on a #200 sieve; they are principally described as clays if they are plastic, andsilts if they are slightly plastic or non-plastic. Major constituents may be added as modifiers and minor constituents may beadded according to the relative proportions based on grain size. In addition to gradation, coarse-grained soils are definedon the basis of their in-place relative density and fine-grained soils on the basis of their consistency.

LOCATION AND ELEVATION NOTES

Percent ofDry Weight

Major Componentof Sample

TraceWithModifier

RELATIVE PROPORTIONS OF SAND AND GRAVEL GRAIN SIZE TERMINOLOGY

TraceWithModifier

DESCRIPTIVE SOIL CLASSIFICATION

BouldersCobblesGravelSandSilt or Clay

Descriptive Term(s)of other constituents

N

(HP)

(T)

(DCP)

(PID)

(OVA)

< 1515 - 29> 30

TermPLASTICITY DESCRIPTION

Water levels indicated on the soil boringlogs are the levels measured in theborehole at the times indicated.Groundwater level variations will occurover time. In low permeability soils,accurate determination of groundwaterlevels is not possible with short term waterlevel observations.

Water Level Aftera Specified Period of Time

Water Level After aSpecified Period of Time

Water InitiallyEncountered

AugerCuttings

ModifiedDames &Moore RingSampler

StandardPenetrationTest

Unless otherwise noted, Latitude and Longitude are approximately determined using a hand-held GPS device. The accuracyof such devices is variable. Surface elevation data annotated with +/- indicates that no actual topographical survey wasconducted to confirm the surface elevation. Instead, the surface elevation was approximately determined from topographicmaps of the area.

Standard Penetration TestResistance (Blows/Ft.)

Hand Penetrometer

Torvane

Dynamic Cone Penetrometer

Photo-Ionization Detector

Organic Vapor Analyzer

STRE

NGTH

TERM

S Standard Penetration orN-Value

Blows/Ft.

Descriptive Term(Consistency)

Descriptive Term(Density)

CONSISTENCY OF FINE-GRAINED SOILS(50% or more passing the No. 200 sieve.)

Consistency determined by laboratory shear strength testing, fieldvisual-manual procedures or standard penetration resistance

Standard Penetration orN-Value

Blows/Ft.

(More than 50% retained on No. 200 sieve.)Density determined by Standard Penetration Resistance

RELATIVE DENSITY OF COARSE-GRAINED SOILS

Hard > 30

> 50 15 - 30Very Stiff

Stiff

Medium Stiff

Very Soft 0 - 1

Medium Dense

SoftLoose

Very Dense

8 - 1530 - 50Dense

4 - 810 - 29

2 - 44 - 9

Very Loose 0 - 3

UNIFIED SOIL CLASSIFICATION SYSTEM

Exhibit C-2

Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests A Soil Classification

Group Symbol

Group Name B

Coarse Grained Soils: More than 50% retained on No. 200 sieve

Gravels: More than 50% of coarse fraction retained on No. 4 sieve

Clean Gravels: Less than 5% fines C

Cu 4 and 1 Cc 3 E GW Well-graded gravel F

Cu 4 and/or 1 Cc 3 E GP Poorly graded gravel F

Gravels with Fines: More than 12% fines C

Fines classify as ML or MH GM Silty gravel F,G,H

Fines classify as CL or CH GC Clayey gravel F,G,H

Sands: 50% or more of coarse fraction passes No. 4 sieve

Clean Sands: Less than 5% fines D

Cu 6 and 1 Cc 3 E SW Well-graded sand I

Cu 6 and/or 1 Cc 3 E SP Poorly graded sand I

Sands with Fines: More than 12% fines D

Fines classify as ML or MH SM Silty sand G,H,I

Fines classify as CL or CH SC Clayey sand G,H,I

Fine-Grained Soils: 50% or more passes the No. 200 sieve

Silts and Clays: Liquid limit less than 50

Inorganic: PI 7 and plots on or above “A” line J CL Lean clay K,L,M

PI 4 or plots below “A” line J ML Silt K,L,M

Organic: Liquid limit - oven dried

0.75 OL Organic clay K,L,M,N

Liquid limit - not dried Organic silt K,L,M,O

Silts and Clays: Liquid limit 50 or more

Inorganic: PI plots on or above “A” line CH Fat clay K,L,M

PI plots below “A” line MH Elastic Silt K,L,M

Organic: Liquid limit - oven dried

0.75 OH Organic clay K,L,M,P

Liquid limit - not dried Organic silt K,L,M,Q

Highly organic soils: Primarily organic matter, dark in color, and organic odor PT Peat

A Based on the material passing the 3-inch (75-mm) sieve B If field sample contained cobbles or boulders, or both, add “with cobbles

or boulders, or both” to group name. C Gravels with 5 to 12% fines require dual symbols: GW-GM well-graded

gravel with silt, GW-GC well-graded gravel with clay, GP-GM poorly graded gravel with silt, GP-GC poorly graded gravel with clay.

D Sands with 5 to 12% fines require dual symbols: SW-SM well-graded sand with silt, SW-SC well-graded sand with clay, SP-SM poorly graded sand with silt, SP-SC poorly graded sand with clay

E Cu = D60/D10 Cc =

6010

2

30

DxD

)(D

F If soil contains 15% sand, add “with sand” to group name. G If fines classify as CL-ML, use dual symbol GC-GM, or SC-SM.

H If fines are organic, add “with organic fines” to group name. I If soil contains 15% gravel, add “with gravel” to group name. J If Atterberg limits plot in shaded area, soil is a CL-ML, silty clay. K If soil contains 15 to 29% plus No. 200, add “with sand” or “with gravel,”

whichever is predominant. L If soil contains 30% plus No. 200 predominantly sand, add “sandy” to

group name. M If soil contains 30% plus No. 200, predominantly gravel, add

“gravelly” to group name. N PI 4 and plots on or above “A” line. O PI 4 or plots below “A” line. P PI plots on or above “A” line. Q PI plots below “A” line.

DESCRIPTION OF ROCK PROPERTIES

Exhibit C-3

WEATHERING Fresh Rock fresh, crystals bright, few joints may show slight staining. Rock rings under hammer if crystalline.

Very slight Rock generally fresh, joints stained, some joints may show thin clay coatings, crystals in broken face show bright. Rock rings under hammer if crystalline.

Slight Rock generally fresh, joints stained, and discoloration extends into rock up to 1 in. Joints may contain clay. In granitoid rocks some occasional feldspar crystals are dull and discolored. Crystalline rocks ring under hammer.

Moderate Significant portions of rock show discoloration and weathering effects. In granitoid rocks, most feldspars are dull and discolored; some show clayey. Rock has dull sound under hammer and shows significant loss of strength as compared with fresh rock.

Moderately severe All rock except quartz discolored or stained. In granitoid rocks, all feldspars dull and discolored and majority show kaolinization. Rock shows severe loss of strength and can be excavated with geologist’s pick.

Severe All rock except quartz discolored or stained. Rock “fabric” clear and evident, but reduced in strength to strong soil. In granitoid rocks, all feldspars kaolinized to some extent. Some fragments of strong rock usually left.

Very severe All rock except quartz discolored or stained. Rock “fabric” discernible, but mass effectively reduced to “soil” with only fragments of strong rock remaining.

Complete Rock reduced to ”soil”. Rock “fabric” not discernible or discernible only in small, scattered locations. Quartz may be present as dikes or stringers.

HARDNESS (for engineering description of rock – not to be confused with Moh’s scale for minerals)

Very hard Cannot be scratched with knife or sharp pick. Breaking of hand specimens requires several hard blows of geologist’s pick.

Hard Can be scratched with knife or pick only with difficulty. Hard blow of hammer required to detach hand specimen.

Moderately hard Can be scratched with knife or pick. Gouges or grooves to ¼ in. deep can be excavated by hard blow of point of a geologist’s pick. Hand specimens can be detached by moderate blow.

Medium Can be grooved or gouged 1/16 in. deep by firm pressure on knife or pick point. Can be excavated in small chips to pieces about 1-in. maximum size by hard blows of the point of a geologist’s pick.

Soft Can be gouged or grooved readily with knife or pick point. Can be excavated in chips to pieces several inches in size by moderate blows of a pick point. Small thin pieces can be broken by finger pressure.

Very soft Can be carved with knife. Can be excavated readily with point of pick. Pieces 1-in. or more in thickness can be broken with finger pressure. Can be scratched readily by fingernail.

Joint, Bedding, and Foliation Spacing in Rock a

Spacing Joints Bedding/Foliation

Less than 2 in. Very close Very thin

2 in. – 1 ft. Close Thin

1 ft. – 3 ft. Moderately close Medium

3 ft. – 10 ft. Wide Thick

More than 10 ft. Very wide Very thick a. Spacing refers to the distance normal to the planes, of the described feature, which are parallel to each other or nearly so.

Rock Quality Designator (RQD) a Joint Openness Descriptors

RQD, as a percentage Diagnostic description Openness Descriptor

Exceeding 90 Excellent No Visible Separation Tight

90 – 75 Good Less than 1/32 in. Slightly Open

75 – 50 Fair 1/32 to 1/8 in. Moderately Open

50 – 25 Poor 1/8 to 3/8 in. Open

Less than 25 Very poor 3/8 in. to 0.1 ft. Moderately Wide a. RQD (given as a percentage) = length of core in pieces Greater than 0.1 ft. Wide

4 in. and longer/length of run. References: American Society of Civil Engineers. Manuals and Reports on Engineering Practice - No. 56. Subsurface Investigation for

Design and Construction of Foundations of Buildings. New York: American Society of Civil Engineers, 1976. U.S. Department of the Interior, Bureau of Reclamation, Engineering Geology Field Manual.

Exhibit C-4

LABORATORY TESTSIGNIFICANCE AND PURPOSE

Test Significance Purpose

California BearingRatio

Used to evaluate the potential strength of subgrade soil,subbase, and base course material, including recycledmaterials for use in road and airfield pavements.

Pavement ThicknessDesign

ConsolidationUsed to develop an estimate of both the rate and amount ofboth differential and total settlement of a structure. Foundation Design

Direct ShearUsed to determine the consolidated drained shear strengthof soil or rock.

Bearing Capacity,Foundation Design,and Slope Stability

Dry DensityUsed to determine the in-place density of natural, inorganic,fine-grained soils.

Index Property SoilBehavior

ExpansionUsed to measure the expansive potential of fine-grained soiland to provide a basis for swell potential classification.

Foundation and SlabDesign

GradationUsed for the quantitative determination of the distribution ofparticle sizes in soil. Soil Classification

Liquid & Plastic Limit,Plasticity Index

Used as an integral part of engineering classificationsystems to characterize the fine-grained fraction of soils, andto specify the fine-grained fraction of construction materials.

Soil Classification

PermeabilityUsed to determine the capacity of soil or rock to conduct aliquid or gas.

Groundwater FlowAnalysis

pH Used to determine the degree of acidity or alkalinity of a soil. Corrosion Potential

ResistivityUsed to indicate the relative ability of a soil medium to carryelectrical currents. Corrosion Potential

R-ValueUsed to evaluate the potential strength of subgrade soil,subbase, and base course material, including recycledmaterials for use in road and airfield pavements.

Pavement ThicknessDesign

Soluble SulfateUsed to determine the quantitative amount of solublesulfates within a soil mass. Corrosion Potential

UnconfinedCompression

To obtain the approximate compressive strength of soils thatpossess sufficient cohesion to permit testing in theunconfined state.

Bearing CapacityAnalysis forFoundations

Water ContentUsed to determine the quantitative amount of water in a soilmass.

Index Property SoilBehavior

Exhibit C-5

REPORT TERMINOLOGY(Based on ASTM D653)

Allowable SoilBearing Capacity

The recommended maximum contact stress developed at the interface of the foundationelement and the supporting material.

AlluviumSoil, the constituents of which have been transported in suspension by flowing water andsubsequently deposited by sedimentation.

Aggregate BaseCourse

A layer of specified material placed on a subgrade or subbase usually beneath slabs orpavements.

Backfill A specified material placed and compacted in a confined area.

BedrockA natural aggregate of mineral grains connected by strong and permanent cohesive forces.Usually requires drilling, wedging, blasting or other methods of extraordinary force forexcavation.

Bench A horizontal surface in a sloped deposit.

Caisson (DrilledPier or Shaft)

A concrete foundation element cast in a circular excavation which may have an enlarged base.Sometimes referred to as a cast-in-place pier or drilled shaft.

Coefficient ofFriction

A constant proportionality factor relating normal stress and the corresponding shear stress atwhich sliding starts between the two surfaces.

ColluviumSoil, the constituents of which have been deposited chiefly by gravity such as at the foot of aslope or cliff.

Compaction The densification of a soil by means of mechanical manipulation

Concrete Slab-on-Grade

A concrete surface layer cast directly upon a base, subbase or subgrade, and typically usedas a floor system.

DifferentialMovement Unequal settlement or heave between, or within foundation elements of structure.

Earth Pressure The pressure exerted by soil on any boundary such as a foundation wall.

ESALEquivalent Single Axle Load, a criteria used to convert traffic to a uniform standard, (18,000pound axle loads).

Engineered FillSpecified material placed and compacted to specified density and/or moisture conditionsunder observations of a representative of a geotechnical engineer.

Equivalent Fluid

A hypothetical fluid having a unit weight such that it will produce a pressure against a lateralsupport presumed to be equivalent to that produced by the actual soil. This simplifiedapproach is valid only when deformation conditions are such that the pressure increaseslinearly with depth and the wall friction is neglected.

Existing Fill (orMan-Made Fill) Materials deposited throughout the action of man prior to exploration of the site.

Existing Grade The ground surface at the time of field exploration.

Exhibit C-6

REPORT TERMINOLOGY(Based on ASTM D653)

Expansive Potential The potential of a soil to expand (increase in volume) due to absorption of moisture.

Finished Grade The final grade created as a part of the project.

Footing A portion of the foundation of a structure that transmits loads directly to the soil.

Foundation The lower part of a structure that transmits the loads to the soil or bedrock.

Frost Depth The depth at which the ground becomes frozen during the winter season.

Grade BeamA foundation element or wall, typically constructed of reinforced concrete, used to span betweenother foundation elements such as drilled piers.

Groundwater Subsurface water found in the zone of saturation of soils or within fractures in bedrock.

Heave Upward movement.

Lithologic The characteristics which describe the composition and texture of soil and rock by observation.

Native Grade The naturally occurring ground surface.

Native Soil Naturally occurring on-site soil, sometimes referred to as natural soil.

Optimum MoistureContent

The water content at which a soil can be compacted to a maximum dry unit weight by a givencompactive effort.

Perched WaterGroundwater, usually of limited area maintained above a normal water elevation by thepresence of an intervening relatively impervious continuous stratum.

Scarify To mechanically loosen soil or break down existing soil structure.

Settlement Downward movement.

Skin Friction (SideShear)

The frictional resistance developed between soil and an element of the structure such as adrilled pier.

Soil (Earth)Sediments or other unconsolidated accumulations of solid particles produced by the physicaland chemical disintegration of rocks, and which may or may not contain organic matter.

Strain The change in length per unit of length in a given direction.

Stress The force per unit area acting within a soil mass.

Strip To remove from present location.

Subbase A layer of specified material in a pavement system between the subgrade and base course.

Subgrade The soil prepared and compacted to support a structure, slab or pavement system.

Documents

Geotechnical Engineering Report - apps.larimer.org Engineering Report South Shore Carter Lake Campground Expansion Larimer County, Colorado July 15, 2016 Terracon Project No. 20165057