
Corresponding analysis category
# Static totalstress analysis
Corresponding analysis models
# Plane strain analysis
# Axisymmetric analysis
Main features

# Stage analysis 


The stage analysis, or the phased construction analysis can be performed.
It is possible to change material parameters, boundary conditions, and
stress release factors at each stage. 

# Shear strength reduction (SSR) analysis 


The shear strength reduction (SSR) analysis can be performed using three
kinds of elasticperfectly plastic constitutive laws. It is possible to
evaluate global safety factor and slip surface by SSR analysis at each
stage. 

# Local factor of safety 


It is possible to calculate the local safety factors at each Gaussian point. 

# Coordination with seepage analysis 


It is possible to use nodal water pressure loads from seepage analysis
(Note: This is for the analysis using load module). 

# Combination of stage and SSR analyses 


It is possible to perform both deformation and stability analyses at the
same time by combining stage and SSR analyses, and to deal with a wide
range of soil related problems such as filled/excavated area, slope stability,
bearing capacity, etc. 

# Mixed assignment of constitutive laws 


It is possible to assign different constitutive laws for each material. 
Boundary conditions
It is possible to define the following four boundary conditions.
# Supporting point (horizontal and vertical rollers, fixed, pin,
enforced displacement)
# Multi point constraint (MPC)
# Spring supporting point
# Pin connection
Element libraries
It is possible to define the following finite elements.
Category 
Element 
2D 
Axisymmetric 
Note 
Line 
Beam 
o 
 
First order element 
Bar 
o 
 
First order element 
Axial spring 
o 
 
Including spring supporting point 
Shear spring 
o 
 
Including spring supporting point 
Torsion spring 
x 
 

Distributed axial spring 
x 
 

Distributed shear spring 
x 
 

Surface 
Threenode triangle 
o 
o 
First order element for 2D & axisymmetric analyses 
Fournode quadrilateral 
o 
o 
First order element for 2D & axisymmetric analyses 
Sixnode triangle 
o 
o 
Second order element for 2D & axisymmetric analyses 
Eightnode quadrilateral 
o 
o 
Second order element for 2D & axisymmetric analyses 
Joint 
Fournode line joint 
o 
o 
Apply between 2D first order elements 
Sixnode line joint 
o 
o 
Apply between 2D second order elements 
o: supported, x: unsupported.
Constitutive law models
# Constitutive law models for elements in plane strain and axisymmetric
analyses
It is possible to use the following constitutive law models for elements
in plane strain and axisymmetric analyses. Linear and laminated elasticity
models can be used as notension materials.
Category 
Constitutive law 
Note 
Elastic 
(1) Linear elasticity 
Isotropic 
(2) Laminated elasticity 
Anisotropic 
nonlinear elastic 
(3) Duncan 1 
Use constant Poisson ration 
(4) Duncan 2 
Define volume coefficient 
(5) Dmin 
Technique by CRIEPI 
Nonlinear 
(6) HD (HardinDrnevich) 

(7) RO (RambergOsgood) 

(8) UWClay (UgaiWakai) 

Elasticperfectly plastic 
(9) MC (MohrCoulomb) 
Associative/nonassociative flow rule 
(10) DP (DruckerPrager) 
Associative/nonassociative flow rule 
(11) MCDP (MohrCoulomb / DruckerPrager) 
Nonassociative flow rule 
Elastoplastic 
(12) PZSand (PastorZienkiewicz) 

(13) PZClay (PastorZienkiewicz) 

Notension 
(14) Linear elasticity 

(15) Laminated elasticity 

# Constitutive law models for beam, bar, spring, and joint elements
It is possible to use the following constitutive law models for beam, bar,
spring, and joint elements.
Element 
Constitutive law 
Support 
Note 
Beam(M ) 
(1) Linear elasticity 
o 

(2) Bilinear x 
x 

(3) Trilinear x 
x 

Bar 
(1) Linear elasticity 
o 

(2) Bilinear 
o 

(3) Trilinear 
x 

Spring 
(1) Linear elasticity 
o 
Including spring supporting point 
(2) Bilinear 
o 
Including spring supporting point 
(3) Trilinear 
x 

Joint 
(1) Linear elasticity 
o 

(2) MC (MohrCoulomb elasticperfectly plasticity) 
o 

o: supported, x: unsupported.
Loads
It is possible to use the following loads.
# Nodal force load (2D, axisymmetric)
# Uniform pressure load (2D, axisymmetric)
# Definedpernode pressure load (2D, axisymmetric)
# Self weight load (2D, axisymmetric)
# Seismic inertia load (2D)
# Nodal water pressure load (2D, axisymmetric)
Note
GeoFEAS2D can take into account water pressure, but not soil permeability.
Postprocessor (Aftertreatment)
Output analysis of processor (Analysis section) is processed.Output / confirmation
of result figures and numerical values are carried out.
In this program, the following can be output mainly.
# Model figure
# Deformation figure
# Vector diagram
# Contour figure
# Distribution map
# Numeric output
Combination with the UC1 Earth retaining work design (Option)
In Temporary sheathing work design, it allows examining the effect to surrounding ground by "enforcement
displacement method" which works vertical overburden pressure on the
bottom of excavation if needed, giving the FEM analysis model that modeled
only ground to the displacement of earth retaining wall from elastoplastic
analysis as enforced displacement.



Elastoplastic result of
Temporary sheathing work 
Earth retaining work FEM
(Input screen of the forced displacement method) 
Earth retaining work FEM
(Contour figure of the forced displacement method) 
Applicable scope
This product is mainly applicable to the following problems.
# Stressdeformation analysis of soil
# Slope stability analysis
# Earth retaining works excavation analysis
# Analysis of surrounding soil effect by shield tunnel construction
# NATM tunnel construction analysis
# Study of water pressure variation effect on soil
# Study of soilstructure interaction
# Ground response acceleration method
References
# Potts, D., Axelsson, K., Grande, L., Schweiger, H. and Long M.:
Guidelines for the use of advanced numerical analysis, Thomas Telford,
2002.
# Zienkiewicz, O. C., Chan, A. H. C., Pastor, M., Schrefler, B. A.,
and Shiomi, T.: Computational Geomechanics with Special Reference to Earthquake
Engineering, John Wiley & Sons Ltd., Chichester, 1999.
# Zienkiewicz, O. C. and Taylor, R. L.: The Finite Element Method
 Fourth Edition , Volumes 1 and 2, McGrawHill, 1989.
