Get assistance! DeepEX Software Q&As

DeepEX Software implements all common methods for the design and analysis of deep excavations systems. In the basic version (software core), the program includes the conventional Limit Equilibrium Method, as well as the Non-linear Analysis method (with use of elastoplastic Winkler springs). Finally, a combined method (LEM+NL) is availabe.  With the Finite Element Analysis additional, optional module, the user can include in the software the advanced FEM engine of the software (DeepFEM) and analyze wall systems with the Finite Element Analysis method, considering full soil-structure interaction.

Conventional Limit Equilibrium Analysis Method (LEM).

Limit equilibrium is an analysis method, where limit state conditions are assumed. For excavations and earth retaining structures this usually means that earth pressures are assumed on both the retained and excavated sides. These pressures may represent a failure state such as active or passive lateral earth pressures, or an assumed redistribution such as diagrams by Peck or FHWA.

In Limit Equilibrium Analysis, the retaining wall is analyzed to provide moment and force equilibrium, when possible. Support reactions are also calculated, typically by using the tributary area method.

Non-Linear (Beam on elastoplastic foundations) Method (NL).

DeepEX implements a non-linear finite element code for the analysis of the mechanical behavior of flexible earth retaining structures during all the intermediate steps of an open excavation. The non-linear engine is empowered by many unique advanced features. DeepEX offers the following elastoplastic soil models:

a) Linear elastic - perfectly plastic

b) Hyperbolic soil model

c) Subgrade reaction soil model

d) Small Strain Hardening model

On the reloading part, every soil model has a linear reloading elasticity parameter. Such a parameter should typically range from 2 to 4 times the loading elasticity value (with average 3). In excavations, the reloading elasticity parameter typically describes the remaining soil below the excavation while the loading elasticity is mostly applicable for soil on the retained side. In a non-linear analysis the excavation models reduced to a plane problem, in which a unit wide slice of the wall is analyzed, as outlined in the Figure below. Therefore, DeepEX is not suitable to model excavation geometries in which three-dimensional effects may play an important role. In the modelling of the soil-wall interaction, the very simple yet popular Winkler approach is adopted. The retaining wall is modelled by means of beam elements with transversal bending stiffness EI; the soil is modelled by means of a double array of independent elastoplastic springs; at each wall grid point, two opposite springs converge at most.

Limit Equilibrium and Non-Linear Analysis Combination Method (LEM+NL).

In this case, DeepEX will first use the LEM method in order to calculate the wall embedment safety factors, and then will run the analysis with the soil springs in order to calculate all other parameters (support reactions, soil pressures, wall moment and shear stresses, wall displacements etc.).

In stepped excavations and deadman wall systems, a part of the passive pressures of the back wall is transferred to the front wall as an active impact load when the LEM or the LEM+NL methods are used. The magnitude of this additional load is affected by several parameters, like the depth of the back wall (thus the passive pressures), the distance between the two walls etc.

Finite Element Analysis Method (FEM).

FEM analysis can consider all construction stage effects and enables us to model full soil-structure interaction. Soil is modelled with a mesh of quadratic triangular finite elements. DeepEX does all the stiffness calculations and helps us to estimate FEM analysis parameters. In FEM, the soil model of each soil type can be defined easily. DeepEX has implemented several models like Mohr-Coulomb, Soil Hardening, Cam Clay and more. It considers drained and undrained clay behavior and it can perform water flow analysis.

DeepFEM can be used within the DeepEX software interactive interface, to analyze composite models like braced excavations with struts and rakers. Anchored walls. Deadman wall systems and more. It can calculate all analysis results – soil and water pressures, wall moment shear and displacement diagrams, support reactions, structural and geotechnical ratios, surface settlements and more. The results can be presented in tables and graphically on the model area for each stage.

Limit Equilibrium and Finite Element Combination Method (LEM+FEM).

In this case, DeepEX will first use the LEM method in order to calculate the wall embedment safety factors, and then will run the analysis with the finite elements in order to calculate all other parameters (support reactions, soil pressures, wall moment and shear stresses, wall displacements etc.). In stepped excavations and deadman wall systems, a part of the passive pressures of the back wall is transferred to the front wall as an active impact load when the LEM or the LEM+NL methods are used. The magnitude of this additional load is affected by several parameters, like the depth of the back wall (thus the passive pressures), the distance between the two walls etc.

The selection of the analysis method is a responsibility of the end user. All methods have certain advantages and limitations, so it is usually highly recommended that we perform all types of analysis and consider the most critical results.

Conventional Limit Equilibrium Analysis Method is usually required.

Non-linear Analysis Method results are usually more realistic, especially in multi-level excavation projects, since the construction staging is taken into consideration.

Finite Element Method is considered to produce very accurate results. It can analyze conditions that consider full soil-structure interaction.

 DeepEX introduces a new additional module, the Finite Element Analysis. The new module enables users to analyze conditions, that consider full soil-structure-interaction. Elasticty models include Linear elastoplastic, and hyberbolic soil models. With the finite element analysis module activated, the software capabilities are greatly expanded and the software can take into consideration neightbouring structures and foundation piles, analyze SEM and TBM tunnels and much more. With FEM, DeepEX provides practically all methods of analysis for deep excavation design.

The basic version does not include Finite Elements, though, our Non-linear analysis engine produces close-to-the-reality wall deflections and wall moments. External comparisons prove that the results using DeepEX are very close to the one produced by other Finite Element analysis programs. 

The software offers the following options for modeling groundwater:

 

1. Hydrostatic: Applicable for both conventional and elastoplastic analysis. In ELP, hydrostatic conditions are modeled by extending the “wall lining” effect to 100 times the wall length below the wall bottom.

Figure: Water pressures – Simplified flow

 

2. Simplified flow: Applicable for both conventional and elastoplastic analysis. This is a simplified 1D flow around the wall. In the NL analysis mode, the traditional NL water flow option is employed.

 

Figure: Water pressures – Hydrostatic pressures

 

3. Full Flow Net analysis: Applicable for both conventional and elastoplastic analysis. Water pressures are determined by performing a 2D finite difference flow analysis. In NONLINEAR, water pressures are then added by the UTAB command. The flownet analysis does not account for a drop in the phreatic line.

 

Figure: Water pressures – Full flownet

 

4. User pressures: Applicable for both conventional and NL analysis. Water pressures defined by the user are assumed. In the nonlinear analysis, water pressures are added by the UTAB command.

Figure: User defined water pressures options in DeepEX

We have checked thoroughly all aspects and methods included in DeepEX. We have performed extensive verification examples, matching deflections from real projects throughout the United States. We can provide on demand an extensive verification document, containing a big number of verification examples, comparing software results with manual calculations and calculated deflections with real-project measurements.

DeepEX software can design any common wall type in minutes. The user can select the preferred wall type and define fast the wall section properties (dimensions, reinforcement, materials). The following wall types are available:

Soldier pile and lagging walls (supported by reinforced concrete piles, prestressed concrete piles, concrete piles with GFRP, H steel beams, steel pipes, steel channels, rectangular hollow steel sections, timber piles and more)

Secant and Tangent pile walls (with steel reinforcement or steel sections)

Sheet pile walls - Steel Sheets and Timber Sheet Piles

Diaphragms (Slurry) walls - Reinforced Concrete Walls

Soldier pile and tremied concrete walls (SPTC)

Combined sheet pile walls (I beams or pipes combined with sheet piles)

Box sheet pile walls

Custom walls, that can be used to simulate any other wall type.

Figure: Wall types in DeepEX

In DeepEX, the user can create several wall sections that can be assigned independently to any wall on the model area (in the same or different examined 2D sections) or to additional wall elements. The list of wall sections is global in the specific project file, meaning that the same or any sections from the list can be used in different walls of different design sections. This allows the user to check fast different alrernatives for the project surrounding walls, use different walls in different project locations, create composite models, as well as design in the same model a temporary excavation and the internal permanent walls.

Figure: Wall sections in DeepEX

In DeepEX it is not only available, but also highly recommended to create all intermediate construction stages in an examined project model. The software calculates and presents results for each stage, which is important since the last stage is not always the most critical one. In Limit Equilibrium Method, each stage is independent, thus wall deflections (and likely wall bending moments) are not realistic for cases with multiple supports. In Non-linear and Finite Element analysis methods a strict staging is required so the methods can converge and produce realistic results. With these methods, the initial stage is geostatic without excavation. Wall deflections and wall moments depend on construction staging.

Figure: Wall deflection diagram, wall moments and support reactions in different stages

In order to change the software default settings, the user account has to have admin rights in the device, since the default file is located in the pc program files. The procedure is to start the software as administrator, open the Settings dialog from the Help tab and press to set the current project as default.

Please review the steps below:

A. With the software closed, take the mouse over the software icon in your Desktop and RIGHT-CLICK on it.

B. From the menu that appears, please select to run the software as administrator.

C. Then, the Default settings dialog can be accessed in the Help tab of DeepEX, perform the changes and select to set current project as Default. This will change the default file that is loaded when the software normally opens.

In DeepEX we can inlcude any commom type of external loads, either on the soil suftwace (strip loads or point loads), or loads directly applied on the wall. A building can be  added on the model area as an external 3D building load, or simulated as an external strip surcharge:

1. Adding a building load:

From the General tab of DeepEX we can select to add a building load and next click on the ground, close to the point where we wish to apply the building load. In the dialog that appears, we can define the exact building position, building size as well as several building properties (number of superstructure/understructure floors, number of columns, beam and column loads etc.):

    

2. Adding a building as an external strip surcharge:

From the General tab of DeepEX, select to add a surface strip surcharge to the model:

 

Click on the model surface on 2 points, close where you wish to apply the building load:

In the dialog that appears we can define the exact load possition, magnitude and type (permanent/temporary). In addition, if we wish to include the building foundation, we can unselect the option “Is Surface”. This way we can also edit the load elevation, defining the foundation level for the load application.

We can change the wall section with depth with the "Additional Wall Elements" tool of the software. This allows the user to actually draw an additional wall element that can be placed either along the main wall, or on the left or right side of the main wall.

The additional wall elements can be used as main or slave walls:

A. Double click on the wall, edit the wall section and create all the wall sections that you need to use in your model.

B. Define the position, top elevation and depth of the main left wall.

C. Press on the arrow next to the option Edit 1st wall of the General tab of DeepEX and select to Draw left wall element (see figure below).

 

 

D. Draw an additional wall element below the main wall (click on 2 points). In the dialog that appears, define the wall section and position of the additional wall.

 

 

In DeepEX software, we can add a series of external surcharges on the model area, in order to simulate any potential traffic loads, construction loads, adjacent structures and more that can affect our excavation site. External loads can graphically be added in the model area, using the draw loads tools provided in the General tab of DeepEX.

 

	Adds a surface surcharge (define the start and end point of the surcharge).
	Adds a surface line load (click a surface point to add a point load).
	Adds a surcharge on the wall (define two wall points to add a surcharge).
	Adds a line load on the wall (define a wall point to add a wall point load)
	Adds a prescribed condition at a wall (click on the wall to add a prescribed condition). A prescribed condition is a predefined displacement or wall rotation (non-linear analysis)
	Adds a footing load (3D) (define a point where to install a footing load).
	Creates a new building (define a point where to install a building).
	Adds a 3D surface load (click on it and draw a 3D load in the Plan view screen).
	Click to manage the elastic load options (see paragraph 4.8).
	Edit load combinations. Load combinations are user defined combinations where a load can be selected manually if it is favorable or unfavorable.
	Assign a load combination. With this option, a load combination can be assigned to a specific design section.

 

DeepEX can design both the temporary and the internal permanent walls. The user can add the permanent walls to the model using the “Draw left/right wall element” tool (see question #16). This allows the user to actually draw an additional wall element that can be placed either along the main wall, or on the left or right side of the main wall. The additional wall elements can be used as main or slave walls.

Figure: External permanent and internal permanent walls in a metro station project designed with DeepEX

In the Analysis tab of DeepEX, we can choose to create a sealed excavation (create a liner effect).

Figure: Sealed excavation option in DeepEX

 

Figure: Water pressure diagram when sealed excavation option is selected

In DeepEX software, in the wall sections dialog, user can define the wall spacing, as well as, the widths to be used in the calculations of the active, passive and water pressures. The following options are available:

- Width d is originally the H beam flange size (if you use H steel beams as soldier piles). These are supposed to be driven piles.

If you wish to convert them to drilled piles, you change the width manually to actually specify the diameter of the hole were the steel beam will be installed and covered with concrete.

If you do reinforced concrete piles, then directly the width d is the diameterth of the concrete pile.

- S is the wall spacing.

For diaphragms and sheet piles you can use the value "1 ft" or "1 m" to review the results on screen per ft (or per meter) of the wall. In general, all the result values reported on screen are divided with the wall spacing to be presented /ft (or /m).

For secant pile walls you define the center to center distance for every other pile. For tangent and soldier piles you define the center to center distance of each pile.

- The Passive, Water and Active widths are the widths used below the excavation for the calculation of passive, water and active pressures respectively.

For continuous walls (like secant piles, tangent piles, diaphragms, sheet piles etc), normally you define the same value to all these parameters (Spacing = Water width = Passive width = Active width).

For non-continuous wall sections like soldier pile walls, there is no lagging below the excavation. In this case it is recommended to take:

For Passive Width: 2.5 to 3 times the pile width d (H beam flange width) (for driven steel piles) or 2.5 to 3 times the pile width d (diameter) (for circular drilled piles). This value is limited by the spacing, so if 2.5*Pile diameter > Spacing, you just use the spacing.

For Water and Active width: These should be equal to the flange or pile diameter, depending on the pile type (as above).

By pressing the "?" button in the wall sections dialog, all these options are presented and explained.

DeepEX software provides a number of warnings after the analysis. Some of these warnings are critical and have to do with check ratios that are not satisfied. These warnings (marked with red) need to be taken seriously under consideration by the user. The software gives some optimization recommendations that can be followed, or the user can edit the model manually.

Some of the provided warnings (marked with orange) are usually general recommendations according to general practice, or things to pay attention.

This message is one of these non critical recommendations, asking to check that the active pressures below the excavation level at not 0.

This can be managed from the Drive pressures drop-down in the Analysis tab of DeepEX, if there is selected the option "Normal" and you see active pressures on the pressure diagrams below the excavation you are fine.

 

The user can create the file in excel and then export it as tab delimited. The file can be of .txt or .cor format.

The files should follow a specific format - 1st row should be parameter names, second row should be the units, and then row by row (without the first column numbering), we need to include four  specific columns as presented in the image below:

After the cpt log import, the user needs to press on the "Process Data" button, so the rest of the properties are estimated:

DeepEX can design cantilever excavations. In Limit Equilibrium Analysis, user can select to use either the Free or the Fixed Earth Method for the cantilever calculations.

Figure: Cantilever excavation in DeepEX

DeepEX can design circular shafts, either cantilever, or supported by ring beams and cap beams.

Figure: Circular excavation with cap beam and ring concrete support in DeepEX

A circular shaft model can be created with the DeepEX Model Wizard. As shown on the instructions below:

Open DeepEX Wizard and select the required unit system.

Figure: Define model unit system

Select the analysis method, and the desired classical earth and water pressures method.

Figure: DeepEX Wizard – Welcome tab

Select the project type and define the basic project properties (final excavation depth, wall length, circular shaft radius, tip of the wall elevation and water table).

Figure: DeepEX Wizard – Dimensions tab

Define the project soil properties and stratigraphy.

Figure: DeepEX Wizard – Soil Layers tab

Define the wall section properties.

Figure: DeepEX Wizard – Wall Type tab

Define supports (cap beam, liner walls, ring beam supports).

Figure: DeepEX Wizard – Supports tab

Define depth for each support level.

Figure: DeepEX Wizard – Stages tab

Define surcharges.

Figure: DeepEX Wizard – Surcharges tab

Define structural and geotechnical codes.

Figure: DeepEX Wizard – Codes tab

 

DeepEX can design dead-man wall systems. The software takes into consideration the earth and water pressures, the external loads, as well as the interaction between the two walls.

Figure: Dead-man wall design in DeepEX

A dead-man wall can be created either by using the DeepEX Model Wizard, or manually in the model area with the tools included in the General tab of DeepEX.

When the model is manually created, then the following stages need to be included:

 

1. Initial Stage: Define wall section properties, soil properties and stratigraphy. No excavation should be performed in the initial stage.

2. Support Installation Stage: In this stage you should draw a ground anchor support (tierod), connecting the two walls. You can define the exact tierod elevation on the wall, the exact spacing between the tierods and the tieback section properties.

3. Backfill Stage: Backfill between the two walls up to the top of the wall elevation.

4. Final Excavation Stage: Excavate to the desired final excavation elevation.

DeepEX can design excavations braced with steel struts and rakers. User can define multiple strut levels, as well as the strut and waler sections. The 3D Frame analysis module of DeepEX can be used to simulate the full shaft with all bracing for each support level.

Figure: Braced excavation in DeepEX – Design Section

A braced excavation can be created either by using the DeepEX Model Wizard, or manually in the model area with the tools included in the General tab of DeepEX.

If you create the model manually(model is manually created), then you have to include the following stages(the following stages need to be included):

1. Initial Stage: Define wall section properties, soil properties and stratigraphy. No excavation should be performed in the initial stage.

2. Excavation Stage: Excavate between the two walls to an elevation below the desired strut installation level. (Repeat for each support level)

3. Support Installation Stage: Draw a strut support, connecting the two walls. You can define the exact strut elevation on the wall, the exact spacing between the strut and the strut section properties. (Repeat for each support level)

4. Final Excavation Stage: In this stage you should excavate to the desired final excavation elevation.

DeepEX can be used for the design and analysis of top-down excavation systems, braced with concrete slabs. Basement and intermediate floor slabs can be added as supports and they can be designed with DeepEX.

Figure: Top-down excavation with concrete slabs in DeepEX

A top-down excavation can be created either by using the DeepEX Model Wizard , or manually in the model area with the tools included in the General tab of DeepEX.

If model is manually created, then the following stages need to be included:

1. Initial Stage: Define wall section properties, soil properties and stratigraphy. No excavation should be performed in the initial stage.

2. Excavation Stage: Excavate between the two walls to an elevation below the desired slab installation level. (Repeat for each support level)

3. Support Installation Stage: Draw a slab support, connecting the two walls. You can define the exact slab elevation on the wall and the slab section properties. (Repeat for each support level)

4. Final Excavation Stage: In this stage you should excavate to the desired final excavation elevation.

DeepEX can design bin-type walls. The two main walls can be connected with tierods and user can choose to excavate outside the walls.

Figure: Bin type wall design in DeepEX

A bin-type can be created either by using the DeepEX Model Wizard, or manually in the model area with the tools included in the General tab of DeepEX.

If the model is created manually, then the following stages need to be included:

1. Initial Stage: Define wall section properties, soil properties and stratigraphy. No excavation should be performed in the initial stage.

2. Excavation Stage: Excavate outside the two walls to an elevation below the desired tierod installation level. (Repeat for each support level)

3. Support Installation Stage: Draw a tierod, connecting the two walls. You can define the exact tierod elevation on the wall and the tierod section properties. (Repeat for each support level)

4. Final Excavation Stage: In this stage you should excavate to the desired final excavation elevation.

DeepEX software can design gravity retaining walls of any shape. This option is available with the additional Gravity Wall module. User has the flexibility to create basic types of retaining walls such as full gravity or with stem. Flexural, reinforcement can be included where ever desired. A gravity wall can also be used as a pier or an abutment wall with piles.

The use of gravity wall in the model can be defined in the “Edit wall data” dialog of DeepEX (Figure 1). When the Gravity wall module is activated, there appears the option “Use gravity wall section”.

The “Edit wall data” dialog appears when user double-clicks on the wall in the Model area of DeepEX.

Figure 1: The Edit wall data dialog with “Use gravity wall section” option.

Then the following option is selected, user should press on the button Edit Section Data. This will cause the “Retaining wall data” dialog to appear (Figure 2). Here, the user can define the retaining wall dimensions and reinforcement.

Figure 2: Retaining Wall Data Dialog

Depending on the selected wall type on the left side of this dialog, several dimension properties are available to be defined (Table 1). The reference coordinate for a gravity wall is taken as the left most corner of the stem (or top of wall). This coordinate is defined from the main wall data dialog.

Table 1: Dimension properties

Height	Total wall height (excluding the key if used)
Base	Total base wall width
Top width	Top of the wall width
Dist. To top left corner	Distance to top left corner from the far left side of the wall
Heel thick	Base thickness on the driving side
Toe width	Distance from the end of the main wall body to the end of the wall toe
Toe thick	Base thickness on the resisting side

The following retaining wall types are available in DeepEX:

 

Symbol/Option	Description
Use key	Select this option in order to use a passive key under the wall
Drain back face	Drains back wall face when the water table is above the wall base

 

Calculate Driving Pressures from edge of wall: In the default mode, stability safety factors are calculated from soil and other pressures directly acting on the driving wall sides. While this assumption gives very good, approximate results, in theory the driving horizontal pressures can be taken at the wall edge. By selecting this option, safety factors are calculated by pressures acting directly on a vertical wall edge that is defined from the left most base coordinate if pressures are driving from left to right or the right most coordinate if pressures are driving from right to left. If this option is selected, then driving soil pressures on this vertical edge are always taken as Active or At-rest.

The reinforcement data table enables the use of reinforcing bars on each wall face. Please note that DeepEX does not account for development lengths and reinforcement bending. It is the final responsibility of the engineer to decide how reinforcement has to be bent, cut, or shaped for fabrication. DeepEX though will calculate and report all bending and shear capacities.

The software provides two options for the wall embedment optimization in Limit Equilibrium Analysis:

A. Define the wall depth manually and check the calculated wall embedment safety factors.

After the analysis is performed, the Analysis summary table appears. There wecan review the most critical results among all stages. We have to make sure that all 3 wall embedment factors (length, passive, rotational) are above a limit (typically this could be 1 , 1.2, 1.3, 1.5 depending how you design).

After we close this summary table, we can still open the Wall Embedment FS results in the results tab of DeepEX for each stage:

B. Automatic wall embedment software optimization use:

When using the Limit Equilibrium Method (LEM), the wall length can be optimized based on the wall embedment safety factors.

 

This option can be located at the Design Tab of DeepEX and it is available only when LEM analysis is selected. There, the required safety factor can be defined for the cantilever stage and for the supported excavation stages. The software will change the wall length to achieve the wanted wall embedment FS.

 

DeepEX offers optimization tools that can help the user to optimize the wall and support sections. Though, the user should select the original wall type and run the analysis. The software keeps the wall type and proposes wall sections that offer enough structural capacity. Th ser can select the ideal section from lists of suitable sections presented by the software.

 

Figure: Optimization tools of DeepEX

 

Figure: Option to optimize the wall section in DeepEX

Figure: Proposed steel beam sections from wall section optimization