Geotechnical_CivilFEM

ANSYS, Inc. Proprietary© 2004 ANSYS, Inc.© 2004 ANSYS, Inc.

SYS C ivilFEM

SYS C ivilFEMGeotechnical module capabilities

• Geotechnical properties library for soils and rocks• Superficial Foundations • Deep Foundations • Retaining wall generation and design (Sheet Piles) • Underground structures (tunnels) • Slope stability analysis • Seepage analysis • Integration with FLAC3D (available in CivilFEM

INTRO)• Other Capabilities

SYS C ivilFEMSoils and Rock Library

Soil classification according to Casagrande’s “Unified

Classification System”

• Library with mechanical, elastic and plastic properties of typical soils and rocks (around 100)

• Definition and use of properties not considered by ANSYS (Atterberg limits, Hoek & Brown coefficients, etc.)

• Correlations among geotechnical parameters from tests or analysis (elasticity modulus versus SPT, etc.)

SYS C ivilFEMSoils and Rock Library

• The user can modify any material property Properties used in a structural analysis

with Ansys.

SYS C ivilFEMSoils and Rock Library

Most common correlations

among properties.

CivilFEM database of correlations. Users can

also define their own correlations!

SYS C ivilFEMSuperficial Foundations

• Footing and continuous foundations:- 2D/3D soil-structure interaction models

SYS C ivilFEMSuperficial Foundations

• Slab Foundations:- 3D soil-structure interaction models - 3D Soil foundation stiffness models with

calculation of precise, average, maximum and minimum values

SYS C ivilFEMLayered Soil Generation

• Automatic generation of equivalent geometrical models of layered soils.

It takes into account the influence of water level

Definition of each layer property

Utility: Ballast module calculation and retaining walls.

Wh

SYS C ivilFEMReinforced Soil

This reinforcement can be used to simulate:

• Sheet or grid reinforcement

• Strip reinforcement

• Soil Nails

• Reinforced slopes or Reinforced Soil walls

CivilFEM will also help to design the reinforcement needed, by calculating if the maximum strength is reached or not.

The common wedge sliding surface (more appropriate for this type of models) can be defined, although the generic polygonal or circular sliding surfaces are also available.

SYS C ivilFEMSoil Foundation Stiffness

• Obtaining the theoretical value of the the soil foundation stiffness, by means of the Winkler model, according to the foundation geometry and earth properties.

Ballast module distribution at each

foundation point

It allows obtaining the theoretical value of the ballast module for any foundation or earth configuration

(including those with stratum).

SYS C ivilFEMSoil Foundation Stiffness

The soil foundation stiffness distribution for different configurations of foundations

SYS C ivilFEMSoil Foundation Stiffness

• The earth layers may be generated using the capability of soil generation.

• The soil foundation stiffness (ballast module) value allows approximating the soil elastic behavior (E, ). Its use avoids the necessity of modeling the earth underneath the structure.

• Furthermore, it may be obtained not only the precise value for each point but also the average, maximum and minimum values of the module throughout foundation.

• The soil foundation stiffness values calculated by CivilFEM are automatically send to ANSYS for the following superstructure calculations with beams shells or solid elements.

SYS C ivilFEMDeep Foundations

• Pile Cap Wizard: - Automatic generation of rectangular, polygonal or circular pile groups

SYS C ivilFEMDeep Foundations

• Pile Cap Wizard: - Pre-Design of the Pile length

SYS C ivilFEMDeep Foundations

• Pile Cap Wizard: - Automatic calculation of the reinforcement amount required according to the selected code

(punching, primary and secondary reinforcement of both sides

for rigid and non-rigid pile caps)

SYS C ivilFEMDeep Foundation

Pile Wailing Load Test Load Test Reinforcement Design

SYS C ivilFEMRetaining Wall Calculation

• CivilFEM performs retaining wall calculation using non-linear and evolving finite element models considering the changing with excavation level

It takes into account the soil-structure interaction using non-linear springs

with contact elements

The wall may be considered as a

non-linear structure and analyzed by the non-linear module of

CivilFEM

SYS C ivilFEMRetaining Wall Calculation

• Calculation of Sheet Piles 2D (automatic wizard) -3D - Non-linear construction sequence analysis - One or two sheet piles can be analysed

simultaneously taking into account anchors, water level, layered soils, applied loads.

The excavation or backfilling process can be visualized in each calculation step.

SYS C ivilFEMRetaining Wall Calculation

• Calculation of Sheet Piles 2D (automatic wizard) -3D - With any ANSYS and CivilFEM cross section- Interaction with other structures

SYS C ivilFEMRetaining Wall Calculation

• The systems generated may consist of one or two screens that can be integrated inside other ANSYS models like a subset.

• The model is solved by means of an evolving calculation, where each calculation stage represents a step in excavation or backfill.

• The reinforcement of the retaining walls can be later designed by CivilFEM.

• With any ANSYS and CivilFEMcross section

SYS C ivilFEM·Earth Pressures

• Dry and flooded earth

• Active, Passive and at rest pressures • Pressures due to the earth weight and overload • Earth pressure for beam, shell or solid elements

Automatic earth pressures on FE Models:

1

X

Y

Z

1

X

Y

Z

SYS C ivilFEMUnderground Structures (Tunnels)

• Terrain Initial Stress • Hoek & Brown Failure Criteria (rocks) • Plastic Constitutive models: 2D/3D Drucker-Prager and 2D

Mohr-Coulomb (plain strain) • Element Birth and Death capability (non-linear construction

sequence analysis)

SYS C ivilFEMTunnels (Terrain Initial Stress)

• The program automatically calculates the initial stress state from the given topography and soil parameters. The initial stresses are stored in an ASCII file

H

H

V

The created initial stress file is

automatically introduced into the

model using the ISFILE command

of ANSYS

SYS C ivilFEMHoek-Brown Failure Criteria

• Hoek & Brown parameters must be defined to perform the analysis according to Hoek & Brown.

• They can be all modified by the user.

• CivilFEM uses its own calculation routine to simulate the behavior of rock foundations following Hoek & Brown criteria.

Only for rocks

SYS C ivilFEMHoek-Brown Failure Criteria

Example of Hoek-Brown failure criteria of a cylindrical hole

SYS C ivilFEMUnderground Structures (Tunnels)

• Element Birth and Death capability (non-linear construction sequence analysis)

SYS C ivilFEMUnderground Structures (Tunnels)

• Plastic Constitutive models: 2D/3D Drucker-Prager and 2D Mohr-Coulomb (plain strain)

SYS C ivilFEMSlope Stability (Classic Methods/FEM)

Generación de fam ilias de poligonales

x1

y12

y11

x2

y22

y21

x5

y52

y51

Polygonal for Janbu Method

R

(x ,y )o o(x ,y )11 11

(x ,y )21 21

(x ,y )12 12

(x ,y )22 22

yF

Generación de fam ilias de círculosGrid of centers for the Fellenius or Bishop

Grid of centers defined by the user.

• CivilFEM allows to calculate the safety factor against sliding phenomena in 2D models defined in ANSYS using Fellenius, Bishop, Morgestern-Price, U.S. Corps of Engineers or Janbu methods.

• The user may also solve the model by finite elements and compute the factor of safety.

SYS C ivilFEMSlope Stability (Classic Methods/FEM)

• Very easy and intuitive way of defining the slope, circles, polygons, water pressures lines, seismic action and so on.

SYS C ivilFEMSlope Stability

• With just one calculation, it’s possible to visualize the results according to the different available methods.

SYS C ivilFEMSeepage Analysis

• Calculating hydraulic heads and pore water pressures• Obtaining the saturation line for 2D problems• Exporting the obtained pore water pressure for slope stability

analysis. The finite element mesh used in the two analyses can be different

SYS C ivilFEMSeepage Analysis

M N

0 3 .333 6 .667 10 13 .333 16 .667 20 23 .333 26 .667 30

0 3.333 6.667 10 13.333 16.667 20 23.333 26.667 30

SYS C ivilFEMIntegration with FLAC3D

SYS C ivilFEMSome Other Capabilities

• Automatic Load Stepping to select suitable load increments • Large strains calculations to perform significant changes in the

geometry • Plastic Constitutive models: 2D/3D Drucker-Prager and 2D Mohr

Coulomb (plain strain), viscoplasticity, viscoelasticity, anisotropic plasticity, etc.

• Safety factors defined as the ratio of the failure load to working load.

• Powerful Post-processor: deformation, stresses, forces, reinforcement amounts, etc

• 2D/3D Dynamic compaction, using the cycling loads

• Improvement of soils: Birth and Death of elements features for jet grouting, gravel column.