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Soil Mechanics: Problems with an Effective Stress Analysis in Abaqus


I'm modelling a sheet pile wall in a cohesion soil with groundwater level placed in the top of the model in Abaqus/Cae.  In this context I want to make an effective stress analysis. I have  establish my initial effective stresses and pore pressures in a Fortran subroutine. As my first step I have made a Geostatic step where the gravitation load is applied.  In the soil material I have specified a soil density of 19.9kN/m^3 and a specific weight of the wetting liquid of 9.82kN/m^3. Further I have specified the hydrostatic water pressure at the boundaries.  I'm using Pore fluid/stress elements.

Unfortunately, when I'm running the analysis my intial effective stresses from Fortran and the effective stresses in the geostatic step do not equilibrate when I'm looking at the vertical stress comonent in the visualization modul.

Have somebody an idea of what I'm making wrong? Is it the wrong type of elements I'm using or should I make another step than the geostatic step?



i want to calculate the effect of encase stone column in clay model to incraese the bearing capacity of clay (increasing the bearing capcity of clay, soil improvemet).

calculate the following :

1-consolidation settlement as a function of time and stress.

2-the the variation of stress in soft soil(ration between horizontal/vertical stress)  with distance from column

3-radial stress on encased material as function to height of encased column

4-pore pressure



 for a  clay sample   that is 5m in diameter and 5 m high confined by an impermeable, smooth, rigid cylindrical container  and encased stone column with diameter 1.0 m and depth 4.8 m . the composite model  subjected to a   surcharge of 20 kPa applied suddenley ,and the clay specimen was subjected to a 9.19 kPa seating pressure as in attach file 11F.cae.

 . The top  surface of the soft clay is permeable. The clay is normally consolidated and has a constant permeability k = 6 .9× 10-10 m/s, and initial void ratio e0 = 1.69. Assume that the clay is elastoplastic, obeying the extended Cam clay model.


Cam clay model parameters




ρ (kg/m3)




k (m/s)

6 ,9× 10-10

Stress ratio, M

1 .11

γw (kN/m3)


p0/2 (kPa)




Wet yield surface size



          Flow stress rate


κ =0.009


ν =0.28


gesynthetic material (ENCASED MATERIAL)
Linear elastic : E= 600 Mpa          
  v= o.3


Weft diameter =5 mm

Hole size=25.4X25.4 mm


                                                                                                tensile strength=140 KN/m

stone material

friction angle = 40
c=1 kpa
dilation angle=0
E= 60 Mpa

v= o.3


the coefficient of sliding friction between the geosynthetic and stone column and between the geosynthetic and the soft soil was assumed to be 0.4 and 0.1 respectively

i want to difine the permeabilty at the surface of stone and clay


the trial files i made

First : I made the model with encased stone column (attach file:RSCOCR1)and it is submit but I want from u to correct it for there were warning message in the file.



second: i made a soft clay model with stone column only (attach file clay stone2.cae), it is not submit

the problem is when i used the following parts (soft clay , stone column , encased material) ,  the model  is not submit when i use different parameter

 i hope u help me to solve the problem in file RSCOCR11mmm.cae

third: when i used another parameter of soft clay and changing the depth of the stone column to 4 m the model is not submit with error message"fixed time increment is too large " , i donot understand why this error message appered.attach file:11F.CAE

*i want an email to attach the previous files.

*in all the previous files the  the Analysis Input File Processor completed successfully but the files were not submit

i think the problem in the initial condition and the interaction module

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