Earthmoving Materials Operations

1Lecture 02ECE 404: Construction Technologies & Processes 1

AUGUST 26, 2015

CHANG-SEON SHON, PH.D., ASSISTANT PROFESSOR

DEPARTMENT OF CIVIL ENGINEERING

NAZARBAYEV UNIVERSITY

LECTURE 2EARTHMOVING MATERIALS &

OPERATIONS

Lecture 02ECE 404: Construction Technologies & Processes 2

EARTHMOVING IS THE PROCESS OF MOVING SOIL OR ROCKFROM ONE LOCATION TO ANOTHER AND PROCESSING IT SO

THAT IT MEETS CONSTRUCTION REQUIREMENTS OF LOCATION, ELEVATION, DENSITY, MOISTURE CONTENT, AND SO ON

EARTHMOVING ACTIVITIES

Excavating / loading / hauling / placing (dumping and spreading) / compacting / grading / finishing

FOR EFFICIENT EARTHMOVING PROCESS,

Accurate estimating of work quantities and job conditions

Proper selection of equipment

Competent job management

EARTHMOVING PROCESS


CHOICE OF EQUIPMENT INFLUENCES ON THE EFFICIENCY & PROFITABILITY OF THE CONSTRUCTION OPERATION

FACTORS THAT SHOULD BE CONSIDERED IN SELECTINGEQUIPMENT FOR A PROJECT

The ability of the equipment to perform the required work

Maximize the profit produced by the equipment

Achieve the lowest cost per unit of production

Possible future use of the equipment

Availability of parts and service

Effect of equipment downtime on other construction equipment and operations

EQUIPMENT SELECTION


BASIC RELATIONSHIP FOR ESTIMATING THE PRODUCTION OF ALLEARTHMOVING EQUIPMENT

=

=

Where,Vol. percycle averagevol. ofmaterialmovedperequipmentCyclesperhour thenumberofcyclesactuallyachieved expected perhour

PRODUCTION OF EARTHMOVINGEQUIPMENT


(From TM 5-331B, U.S. Department of the Army)

JOB EFFICIENCY FACTORS FOR EARTHMOVING OPERATIONS

PRODUCTION OF EARTHMOVINGEQUIPMENT (CONTD)


TRAFFICABILITY

Ability of a soil to support the weight of vehicles under repeated traffic

Function of soil type and moisture conditions

Factors impacting soil trafficability

Soil strength / Slipperiness / Stickiness / Slope / Stoniness

Drainage, stabilization of haul routes, or the use of low-ground pressure construction equipment may be required when poor trafficability conditions exist

EARTHMOVING MATERIALS: GENERAL SOIL CHARACTERISTICS


LOADABILITY

Measure of the difficulty in excavating and loading a soil

E.g. Loose granular soils vs. compacted cohesive soils and rock

UNIT SOIL WEIGHT (LBS/YD3 OR KG/M3)

Used as measure of compaction

Factor in determining the capacity of a haul

Depend on soil type, moisture content, and degree of compaction

MOISTURE CONTENT

GENERAL SOIL CHARACTERISTICS(CONTD)

=

100


SOIL IDENTIFICATION ANDCLASSIFICATION

SOIL

Consist of gravel, sand, silt, clay, and organic materials

2m

m


SOIL CLASSIFICATION

SOIL CLASSIFICATION SYSTEMS

Two principal soil classification systems are used for design and construction in the United States

Unified System

AASHTO System (American Association of State Highway and Transportation Officials)

In both systems, soil particles 3 in. or larger in diameter are removed before performing classification tests.


SOIL CLASSIFICATION: UNIFIED SOIL CLASSIFICATION SYSTEM (USCS)

STEP 1. DETERMINE ATTERBERG LIMITS

Plasticity index (PL) = Liquid limit (LL) - Plastic limit (PL)


STEP 2. CONDUCT SIEVE ANALYSIS AND DETERMINE SOIL GROUPON THE BASIS OF PI AND R200

SOIL CLASSIFICATION: USCS (CONTD)


STEPS 3-6. DETERMINE R4 CONTENT AND GET RATIO OFR4/R200. THEN, DETERMINE SOIL TYPE USING THE FOLLOWINGTABLES.

SOIL CLASSIFICATION: USCS (CONTD)


SOIL CLASSIFICATION: AASHTO SYSTEM

AASHTO SYSTEM OF SOIL CLASSIFICATION

Courtesy of BOMAC Americas


SOIL CLASSIFICATION: GRADATION CURVE

Typical gradation curves for coarse-grained soils. (U.S. Army Engineer School)


SOIL CLASSIFICATION: FIELD IDENTIFICATION

UNIFIED SYSTEM OF SOIL CLASSIFICATION : FIELD IDENTIFICATION

Weight passing

in. (6mm) passing materials : < 50% : gravel

50% : sand

No.200 (75m) passing materials

< 10% : well or poorly graded

10% : High or low plasticity


SOIL CLASSIFICATION: FIELD IDENTIFICATION (CONTD)

DRY STRENGTH TEST AND PLASTICITY


SOIL SHAKING TEST

Place soil in palm of hand

Add water gradually and knead the soil until it begins to get sticky

Form a ball about in. (19mm) in diameter

Hold the ball in one hand and tap the back of the hand with the other

If the ball becomes wet and shiny, it is mostly fine sand or silt

No reaction suggests clay

SOIL CLASSIFICATION: FIELD IDENTIFICATION (CONTD)


CONSTRUCTION CHARACTERISTICSOF SOILS

10


BASIC RULE OF EARTHWORKS OPERATION

Cut for the high

Fill for the low

EARTHWORK OPERATION


EARTHWORK OPERATION : FILL & CUT

11


SOIL VOLUME-CHANGECHARACTERISTICS

TYPICAL SOIL VOLUME CHANGE DURING EARTHMOVING

Most excavated materials are found to increase in volume after excavation (bulking or loosing)

When compacted in the in-situ volume, soils occupy less volume (shrinkage)


SOIL CONDITIONS

Bank: Material in its natural state before disturbance. Often referred to as in-place or in-situ. A unit volume is identified as a bank cubic yard (BCY) or a bank cubic meter (BCM).

Loose: Material that has been excavated or loaded. A unit volume is identified as a loose cubic yard (LCY) or loose cubic meter (LCM).

Compacted: Material after compaction. A unit volume is identified as a compacted cubic yard (CCY) or compacted cubic meter (CCM).

SOIL VOLUME-CHANGECHARACTERISTICS (CONTD)

12


SWELL


% =()

() 1 100

EXAMPLE

Find the swell of a soil that weight 1661 kg/m3 in its natural state and 1186 kg/m3 after excavation.


SHRINKAGE


% = 1 ()

() 100

EXAMPLE

Find the shrinkage of a soil that weight 1661 kg/m3 in its natural state and 2077 kg/m3 after compaction

13


LOAD FACTORS

SHRINKAGE FACTOR (COMPACTION FACTOR)


=()

()or

=1

1 +

=()

()or

= 1


LOAD AND SHRINKAGE FACTORS

EXAMPLE

A soil weighs 1163 kg/LCM, 1661 kg/BCM, and 2077 kg/CCM

Find the load factor and shrinkage factor for the soil

How many bank cubic meters (BCM) and compacted cubic meters (CCM) are contained in 593330 loose cubic meters of this soil?


14



TYPICAL SOIL WEIGHT AND VOLUME CHANGE CHARACTERISTICS*


WHEN PLANNING AND ESTIMATING EARTHWORK, IT ISFREQUENTLY NECESSARY TO DETERMINE THE SIZE OF THE PILE OF

MATERIAL THAT WILL BE CREATED BY THE MATERIAL REMOVED

FROM THE EXCAVATION

If the pile of material is long in relation to its width, it is referred to as a spoil bank.

SPOIL BANKS OR PILES

15


DETERMINE THE DIMENSIONS OF SPOIL BANKS OR PILES

Convert the volume of excavation from in-place condition (BCY or BCM) to loose conditions (LCY or LCM)

TRIANGULAR SPOIL BANK

SPOIL BANKS OR PILES (CONTD)


CONICAL SPOIL PILE


16


TYPICAL VALUES OF ANGLE OF REPOSE OF EXCAVATED SOIL



EXAMPLE 1

Find the base width and height of a triangular spoil bank containing 76.5 BCM if the pile length is 9.14 m, the soil's angle of repose is 37, and its swell is 25%.


17


EXAMPLE 2

Find the base diameter and height of a conical spoil pile that will contain 76.5 BCM of excavation if the soil's angle of repose is 32and its swell is 12%.



WHEN PLANNING OR ESTIMATING AN EARTHMOVING PROJECT, IT IS OFTEN NECESSARY TO ESTIMATE THE VOLUME OF MATERIAL

TO BE EXCAVATED OR PLACED AS FILL

THE PROCEDURES TO BE FOLLOWED CAN BE DIVIDED INTOTHREE PRINCIPAL CATEGORIES:

Pit excavations (small, relatively deep excavations such as those required for basements and foundations)

Trench excavation for utility lines

Excavating or grading relatively large areas

PROCEDURES SUGGESTED FOR EACH OF THESE THREE CASES AREDESCRIBED IN THE FOLLOWING SECTIONS.

ESTIMATING EARTHWORK VOLUME

18


SMALL, RELATIVELY DEEP EXCAVATIONS SUCH AS THOSEREQUIRE FOR BASEMENTS AND FOUNDATION

Divide the horizontal area into a convenient set of rectangles, triangles, or circular segments

Calculate total area (the sum of the segment areas)

Calculate the average depth

Calculate volume

ESTIMATING EARTHWORK VOLUME: PIT EXCAVATIONS

=


EXAMPLE

Estimate the volume of excavation required (bank measure) for the basement shown. Values shown at each corner are depths of excavation. All values are in meter.

ESTIMATING EARTHWORK VOLUME: PIT EXCAVATIONS (CONTD)

19


TRENCH EXCAVATION FOR UTILITY LINES

Calculate the trench cross-section area

Measure the linear distance along the trench line

Calculate volume

ESTIMATING EARTHWORK VOLUME: TRENCH EXCAVATIONS

=


CROSS-SECTIONAL AVERAGE METHOD

ESTIMATING EARTHWORK VOLUME: TRENCH EXCAVATIONS (CONTD)

= +

2

=1

2

+ 2

+

2

=1

6 + 4 +

: ,

20


EXAMPLE

Find the volume (bank measure) of excavation required for a trench 0.92 m wide, 1.83 m deep, and 152 m long. Assume that the trench sides will be approximately vertical.

ESTIMATING EARTHWORK VOLUME: TRENCH EXCAVATIONS (CONTD)


EXCAVATING OR GRADING RELATIVELY LARGE & COMPLEX AREAS

Divide the area into a grid indicating the depth of excavation or fill at each grid intersection

Assign the depth at each comer or segment intersection a weight according to its location (number of segment lines intersecting at the point)

Interior points : a weight of four

Exterior points : a weight of two

Corner points : a weight of one

ESTIMATING EARTHWORK VOLUME: LARGE AREAS

=

21


EXAMPLE

ESTIMATING EARTHWORK VOLUME: LARGE AREAS (CONTD)



1 4 3 4

1 1 2 2 4

2 2 2 3 4

5 1 2 3 4

1 2 3 4

4

4

4

4

2 3 44

abV y y y y

abV h h h h

abV h h h h

abV h h h h

abV h h h h

SQUARE PILLAR

22



1 4 3

1 1 4 4

2 3 4 4

6 1 2 4

1 2 3 8

6

6

6

6

2 3 86

abV y y y

abV h h h

abV h h h

abV h h h

abV h h h h

PRISM


EXAMPLE

Find the volume of excavation required for the area shown in Figure. The figure at each grid intersection represents the depth of cut at that location.


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EARTHWORK CALCULATION SHEET(TABLE)

Area (m2)

*Average

Area

(m2)

**Vol. of

soil

(m3)

Area

(m2)

Average

Area

(m2)

Vol. of

soil

(m3)

Compaction

factor

(C)

1Revised

Vol.

(m3)

11 21.6 8.3 963.3

12 20 29.4 25.5 510.0 1.3 4.8 96.0 0.9 106.7 403.3 1366.6 106.7

13 12.5

14 7.5

15 20

16 20

Total

* Average area is the average of previously and currently measured areas

**Volume of soil = Average area x distance1Revised vol. of soil = vol. of soil / compaction factor2"+" means cutting of soil while "-" imply filling of soil3Cumulative vol. of soil4At the same station no, select small vol. of soil betwwen cutting and filling of soil

Cutting of soil (Used in fiiling) Filling of soil 2Calculated

Soil (m3)

Excess (+)

Short (-)

3Cumulative

Vol.

(m3)

4Vol. (m3)

horizontal

direction

Station No. Distance

EARTHWORK CALCULATE SHEET (TABLE) IS REQUIRED TO DRAWMASS DIAGRAM


EARTHWORK CALCULATION TABLE: HIGHWAY CONSTRUCTION

24


IN ORDER TO MINIMIZE MATERIAL WASTE OR BORROW, IT ISNECESSARY TO PRODUCE WHAT IS CALLED A MASS HAULDIAGRAM

A PLOT OF CUMULATIVE VOLUME OF SOIL AGAINST DISTANCEALONG THE ROAD

CUT VOLUMES ARE TAKEN TO BE POSITIVE AND FILL VOLUMESTO BE NEGATIVE

COMMON IN ROADWAY OR AIRFIELD

PREPARED BY HIGHWAY AND AIRFIELD DESIGNERS TO ASSIST INSELECTING AN ALIGNMENT

MASS (HAUL) DIAGRAM


MASS (HAUL) DIAGRAM (CONTD)

25


THE VERTICAL COORDINATE OF THE MASS DIAGRAM CORRESPONDING TOANY LOCATION ON THE ROADWAY PROFILE REPRESENTS THE CUMULATIVE

EARTHWORK VOLUME FROM THE ORIGIN TO THAT POINT

WITHIN A CUT, THE CURVE RISES FROM LEFT TO RIGHT

WITHIN A FILL, THE CURVE FALLS FROM LEFT TO RIGHT

A PEAK ON THE CURVE REPRESENTS A POINT WHERE THE EARTHWORKCHANGES FROM CUT TO FILL

A VALLEY (LOW POINT) ON THE CURVE REPRESENTS A POINT WHERE THEEARTHWORK CHANGES FROM FILL TO CUT

WHEN A HORIZONTAL LINE INTERSECTS THE CURVE AT TWO OR MOREPOINTS, THE ACCUMULATED VOLUMES AT THESE POINTS ARE EQUAL. THUS, SUCH A LINE REPRESENTS A BALANCE LINE ON THE DIAGRAM.

MASS (HAUL) DIAGRAM (CONTD)


CONSTRUCTION USE OF THE MASSDIAGRAM (CONTD)

USING THE MASS DIAGRAM

The length and direction of haul within a balanced section

The average length of haul for a balanced section

The location and amount of borrow (material hauled in from a borrow pit) and waste (material hauled away to a waste area) for the project

Selection of type of equipment for accomplishing the work

Selection of construction method

26


CONSTRUCTION USE OF THE MASSDIAGRAM (CONTD)

EXAMPLE

Figure 1 shows the mass diagram of earthwork.

(1) What is the total amount of soil (m3) between A and B?

(2) What is the average distance (m) between A and B? Figure 1. Mass diagram

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Earthmoving Materials Operations