Tutorial 6: Excavation outside of two walls connected with a tieback

Tutorial 6: Bin type walls with tierod

Deep Excavation LLCDeepEX 2015 – Advanced course 1

DeepEX is a software program for braced excavations in soils with 2D limit-equilibrium and non-linear analysis

methods, and structural verification of all elements (with AISC, ASD, Eurocodes).

It offers the ability to analyze walls with multiple braces (tiebacks) in multilayered soils.

The non-linear analysis considers elastoplastic behavior for the whole soil-wall-support system.

The program also offers the ability to perform traditional limit-equilibrium analyses.

The graphical interface is completely interactive and the input is simplified to a great extend.

The program utilizes archives of wall types, structural and soil materials, ground anchors etc.

The analysis can be performed in either an utlimate state or at a service state (allowable design, LRFD, or Eurocode 7

design approach methods).

The program offers the ability to automatically set all critical settings according to the desired design methodology.

Corso Paratie, Milano 30 settembre 2009

INTRODUCTION

DeepEX 2015 – Advanced course 2

Program layout

Wall selection

Project tree view

Design section list(right click)

General input tabsFile menu (click)

Model stages (right click options similar to

excel)Command prompt (enter coordinates)

Press to perform calculations.

Instruction box

Model space (left or right click on any item)

Mouse is over item Units

DeepEX 2015 – Advanced course

3D Model (Frames)

View and other

Enter basic project information1. Select this button

2. Define the project name etc.

3. Press OK


Move model elevations1. Select this button

2. Set new reference elevation to 100 ft

3. Check All boreholes (this moves all soil

layers)

4. Press OK

1. Add a 2nd wall2. Double click on right wall3. Change dimensions3.1 Change xwall= 60ftDepth L= 45ft

Define basic model limits (top, bottom, left, right)

1. Select this button

2. Set Top= 130ftBottom= 40ft

Left= -60ftRight= 120ft

3. Press OKDeepEX 2015 – Advanced course

Modify soil types (database of soils)1. Select this button.

Or

Expand the Soils Tree and Double click on FOptions: Right click or press Delete

Note: In DeepEX you can use any soil type in more than one borehole. For example the F soil can be used in boring 1 or boring 2 etc.

You can use any Boring on any design section. Thus changing any property of the F soil will affect all the excavation Design Sections where F is used!

Boring with F soil

Soil type data form

Available soil types

Add new, copy, delete, paste soil

DensityStrength

Short soil name, description and color.

Soil type & initial clay behavior

Test data for estimating soil properties


Soil type continuedSoil properties: GeneralSoil name: F (this appears in the boring)Description: Detailed soil description.Soil type: Sand gt= 125 kcf : Total unit weightgdry= 120 kcf : Dry unit weight (above water table)c‘= 0 : Effective cohesionF’= 30 degrees : Effective friction angle

v= 0.35 Poisson’s ratio

Kx = Horizontal permeabilityKz = Vertical permeability

Parameters only for claysSu = Undrained shear strengthFcv= Constant volume shearing angleFpeak= Peak shearing angle


Soil properties (Resistance and Elastic)

KoNC = At rest lateral earth pressure coefficient for normally consolidated state.

Enter elasticity values as shown before. Click on > buttons for more options.


Soil S1Soil properties: Change S1A. GeneralSoil name: S1 (this appears in the boring)Description: Sand Detailed soil description.Soil type: Sand gt =125 pcf : Total unit weightgdry= 120 pcf: Dry unitc‘ 0: Effective cohesionF’ = 36 degrees : Effective friction angleV = 0.35 Poisson’s ratio

C. Elasto-plasticE = 500 ksfrEur = 3

D. BondUltimate bond = 30 psi

Press OK

Edit Borings (soil layers)To edit the soil layers double click on the model boring.

The borings can also be edited from:

a) Edit Borings Button.

Or from the:

b) Tree View – Stratigraphy – boreholes

Double click here (or right click) with the mouse.


Enter Soil LayersTo edit the soil layers click on the blue button and enter the top of layer elevation.

For this example type 90 here:

Then select soil type S1 here:


Press OK


Double click on wall


2. Select edit section data, to change wall properties

1. Change wall depth to 45ft


Number of nodes controls the divisions

along the wall in a limit-equilibrium analysis.

(Suggested 200 min, or set so that small

intervals (0.25 ft) are generated)

Change wall section AZ 19 sheet pile

1. Change wall type

2. Select AZ-19 section

3. Select A50 steel(fy= 50 ksi)

4. Select OK


Wall using AZ-19 wall section

Select OK


Add a new stage (Model Tab)

Or right click (to add a stage, similar to Excel)


Stage 1 change external elevations to El. 90

Stage 1


Add Stage 2: Add a strut at El. +92

Right click and add stage 2


Select tool to add a tieback

Note: After selecting the “Draw ground anchor button” the program tells you to select/enter the 1st tieback point at the wall (x z)


Add tieback with mouse1. Select 1st point on left wall (we will modify the coordinates later)

2. Select 2nd point on right wall when wall highlights

Edit tieback properties (support options)1. Change dimensions z= 92 ft (elevation)Horizontal spacing to 5ft (length is determined by program)

Select OK


Edit tierod section to #18 bar – 80ksi• Select solid bar• Change grade to 80• Select #18 bar• Specify one bar per

tierod• Dfix does not play a

role


Add a surcharge on the center surface. Select this tool button.


Add surcharge with mouse

2. Select 2nd point

1. Select 1nd point on left


Modify surcharge

1. Change coordinates X1= -22 X2= -2

2. Change surchargeqz1= 0.6 ksf qz2= 0.6 ksf

Point 1 is on the left sidePoint 2 is on the right side

3. Select OK


Wall index refers to which wall the load is

applied: 0 = left wall, 1= right wall, -1 all walls

Add stage 3: Excavate to El. 80ft left and right side

Right click and add stage 3


On stage 3: Go to Analysis tab

1. Change analysis mode to “Limit Equilibrium and Beam Elastoplastic Foundations”


In this mode, DeepEX first performs a limit-equilibrium analysis and stores the conventional wall embedment safety factors. Then, DeepEX runs the elastoplastic solution (non-linear) and stores wall moments, shears, displacements and other parameters from the non-linear analysis.

No wall friction to be used• Wall friction (wall to soil) is ignored because walls are not expected to

experience vertical movement (Analysis tab)

Select US structural codes (Design Tab)1. Select US allowable settings from Design tab


1. Concrete code and Steel Code(1.6 is safety on Ultimate cap)

2. Clay behavior

3. Water pressure analysis

4. Driving pressures Ka = Active without wall friction5. Resisting pressures Kp/1.5 = Passive divided by 1.56. Table displays assumptions for both limit-equilibrium and non-

linear analysis

Review Assumptions (Yellow table Stage 2)


Analyze the model (current design section)


Analyzes all design sections

Summary table (all Design sections)


Summary table (Selected design section all stages)

Note: You may select another design section or another wall (when a 2nd wall is used) Press EXIT


Results Tab (for viewing results on model screen)

Wall embedment and other safety factors

Wall moment, shear, axial, displacement.Support reaction R.

Display wall capacity (moment and shear), Stress ratios(ratios <1 OK)

Display stresses and pressures on walls.

Display soil mass stresses (when water flownet analysis is performed)

Click on Min-Max to display min and max values.Show ENV= Show result envelope (this design section)

Tables and diagrams


Results on model

Documents

Tutorial 6: Excavation outside of two walls connected with a tieback