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DeepEX 2020

Solving Deep Excavation Design

DeepEX 2017 talk to it and design your deep excavation!

Deep Foundation Software, Pile Rafts, Pile Groups

From soil estimation to axial and lateral pile capacity

DeepFND - Deep Foundation Software, caissons, CFA, drilled piles, driven piles, concrete, timber

From soil estimation to helical pile settlement estimation.

New helical pile software HelixPile
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What do you want to design?
DeepFND 2020: Deep Foundation software (NEW: Pile-Group/Pile Raft Analysis!)
DeepEX 2020: Deep Excavation software
Soldier pile walls
Sheet pile walls
Secant pile Walls
Tangent piles
Diaphragm Walls
Soldier and Tremied Concrete
Soil Mix walls
Combined king pile sheet piles
Slope stability
Cost estimation for braced excavations
Waler-Strut Cofferdams
Snail-Plus 2019: Soil nailing - soil nailing walls
SiteMaster: Inclinometer software (adopted by Geokon)
HelixPile: Helical Pile Software
RC-Solver: Concrete Design ACI-318, EC2, EC8
Steel-Beam: Steel beam column design, full equations, AISC, EC3

Secant pile walls with strut supports, English units

A. Project description

In this example we will design two secant pile wall supported by strut supports, supporting a 40 ft excavation. Tables 1 and 2 present the soil properties and the stratigraphy respectively. Table 3 presents the external loads. Table 4 presents the wall properties. Table 5 presents the support properties. The ground elevation next to the wall is 4 m , and the general ground Elevation is 24 ft. The general water elevation is -8 ft.

Table 1: Soil properties

Name

Soil Type

Φ'

(deg)

c'

(psf)

Su

(psf)

γt

(pcf)

γdry

(pcf)

Kx

ft/sec

Kz

ft/sec

Eload

ksf

Eur

ksf

qskin,u

psi

MDS

Sand

34

0

-

121

121

0.00038

0.00038

636

1278

7.2

VDS

Sand

41

0

-

124.2

124.2

0.00038

0.00038

1252

3757

21.8

Table 2: Stratigraphy (Boreholes)

Soil Layer Name

Top Elevation (m)

OCR

Ko

MDS

24

1

0.441

VDS

0

1

0.344

Table 3: External loads

Name

Type

Position

(X0,Z0)

(X1,Z1)

Q0

Q1

0

Surcharge

On the ground

(-42,24)

(-24,24)

0.3 ksf

0.3 ksf

1

Surcharge

On the ground

(52,24)

(78,24)

0.2 ksf

0.2 ksf

2

Moment

On the wall

(1,10)

-

-2.25 k-ft/ft

-

3

Moment

On the wall

(27,10)

-

3.5 k-ft/ft

-

4

Point load

On the ground

(-3,14)

-

0.6 ksf

-

5

Point load

On the ground

(33,14)

-

0.9 ksf

-

6

Point load

On the wall

(0,6.5)

-

0.7 ksf

-

7

Point load

On the wall

(26,6.5)

-

-1 ksf

-

Table 4: Wall properties

Type

Secant pile wall

Concrete

Fc 5 ksi

Steel

Grade 80

Top Elevation (ft)

14

Height (ft)

72

Pile Diameter (ft)

2

Hor. Spacing (ft)

3

N of rebars / pile

10

Top bars #

#8

Shear reinf. #

#4

Shear reinf. ver. Spacing, Sv (in)

5

Table 5: Support properties

Name

Type

Elevation on the wall (ft)

Angle (deg)

Free length (ft)

Fixed length

(ft)

Hor. Spacing

(ft)

Section

0

Strut

12

0

24

-

10

PP24X2.5

1

Strut

-2

0

24

-

10

PP24X2.5

2

Strut

-14

0

24

-

10

PP24X2.5

B. Modeling with DeepEX

B1. Use of DeepEX

Figure 1: Edit soil properties dialog.

Figure 2: Edit soil layers dialog.

Figure 3: Edit wall properties dialog.

Figure 4: Wall data dialog

Figure 5: Support options.

After drawing the support on the model, the Edit support data dialog appears (i.e. for tieback supports, Figure 6).

Figure 6: Edit support data dialog.

Figure 7: Load options.

After drawing the load on the model, the Edit surcharge dialog appears (i.e. for sitrip surcharges, Figure 8).

Figure 8: Edit distributed load dialog.

Figure 9: Surface options.

Figure10: Water elevation – settings.

With the draw custom water surface tool, we can draw a non-horizontal groundwater table. To do this, select this option and then start clicking the left mouse button from left to right (press enter to complete). To delete the custom water line, move on top in the model and press delete.

The draw a U line tool is used to draw a line of constant pore pressure in the model. This line is only used in slope stability analysis.

The define user water pressures tool launches the dialog for defining custom values of water pressures next to the walls. Please note that in the non-linear engine, two consecutive zero values of water pressure still count in increasing the total vertical stress by γw (see theory manual).

Figure 11: Ground water table.

B2. Example simulation

In DeepEX 2014 we can design our projects using construction stages. After the model is designed, the software calculates each construction stage, reassuring that the model is stable, since the last stage is not always the critical one. Next, we provide the steps in each construction stage, in order to simulate the project in DeepEX.

  1. Define the soil properties

  2. Define the soil layers (stratigraphy)

  3. Define the wall section and wall properties

Figure 12: Model, Stage 0.

  1. Create slope surfaces on the left and right side of the walls, activate the walls and external loads.

Figure 13: Model, Stage 1.

1. Excavate between the two walls to elevation 3.4 m.

1. Apply first strut row at elevation 3.7 m.

1. Excavate between the two walls to elevation -1.1 m.

1. Apply second strut row at elevation -0.8 m.

1. Excavate between the two walls to elevation -4.6 m.

1. Apply second strut row at elevation -4.3 m.

1. Excavate between the two walls to elevation -8 m.

Figure 14: Model, Stage 8.

In DeepEX we can design several design sections in the same model. We can add new design sections as new or as copies of the existing ones, doing several modifications in the model, or just defining different standards, calculation or analysis methods.

  1. Results in DeepEX

Since the model is ready, we can choose to calculate the design section, pressing on the button .

After the analysis is succeeded, the Summary table appears. Table 6 below includes some critical checks and values for each construction stage. Figures 15 to 18 present some graphical results from the results tab of DeepEX.

Table 6: DeepEX critical results/stage

Figure 15: Moment diagrams, Stage 8.

Figure 16: Shear diagrams, Stage 6.

Figure 17: Wall deflection diagrams, Stage 8.

Figure 18: Effective horizontal soil pressures, Stage 4.

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