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<title>[Geoqus] On Geostatic Step</title>
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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Manooch,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>to incorporate the field stresses, I would
use:<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>*initial conditions, type=stress<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>and<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>*initial conditions, type=pore pressure <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>and <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>*initial conditions, type=ratio<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>To keep the stresses in your model, either
make your mesh large enough and hold the outside boundary in 1,2 direction, or
use the infinite element as Jose pointed out. Be aware that you should provide
effective stresses, not total stresses.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Please note that from your part of the
input file it looks like you want to calculate time dependent pore pressure
(although you call your step “equilibrium step”). If you want to
calculate the equilibrium only them remove “</span></font><font size=2><span
style='font-size:10.0pt'>consolidation, end=PERIOD”, </span></font><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'>it probably makes convergence also more likely, and you don’t
have to worry about the permeability of your material. As soon as you
understand your model, you can switch to time-dependent modeling, and start
playing with the permeability (and unit system).<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Good luck,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Wouter<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>
geoqus-bounces+wvanderzee=geomi.com@lists.ruhr-uni-bochum.de
[mailto:geoqus-bounces+wvanderzee=geomi.com@lists.ruhr-uni-bochum.de] <b><span
style='font-weight:bold'>On Behalf Of </span></b>Manooch Salehabadi<br>
<b><span style='font-weight:bold'>Sent:</span></b> Tuesday, March 27, 2007 3:52
PM<br>
<b><span style='font-weight:bold'>To:</span></b> Geoscientific Abaqus User
Group<br>
<b><span style='font-weight:bold'>Subject:</span></b> Far Field Stresses</span></font><o:p></o:p></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<div id=idOWAReplyText62246>
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<p><font size=2 face="Times New Roman"><span style='font-size:10.0pt'>Dear All,<o:p></o:p></span></font></p>
<p><font size=2 face="Times New Roman"><span style='font-size:10.0pt'>hi and
sorry for this simple question , i am just a beginner with ABAQUS.<o:p></o:p></span></font></p>
<p><font size=2 face="Times New Roman"><span style='font-size:10.0pt'>i am
trying to model a bore hole in mohr coulomb media (rock) with plain strain
element CPE8RP, but i do not know how <o:p></o:p></span></font></p>
<p><font size=2 face="Times New Roman"><span style='font-size:10.0pt'>to
include far field stress in the model?<o:p></o:p></span></font></p>
<p><font size=2 face="Times New Roman"><span style='font-size:10.0pt'>i have
used simple hollow cylindrical model with loading as following to simulate far
field stresses:<o:p></o:p></span></font></p>
<p><font size=2 face="Times New Roman"><span style='font-size:10.0pt'> <o:p></o:p></span></font></p>
<p><font size=2 face="Times New Roman"><span style='font-size:10.0pt'>*Step,
name="Equilibrium Step", nlgeom=YES<o:p></o:p></span></font></p>
<p><font size=2 face="Times New Roman"><span style='font-size:10.0pt'>*Soils,
consolidation, end=PERIOD, utol=10., creep=none<o:p></o:p></span></font></p>
<p><font size=2 face="Times New Roman"><span style='font-size:10.0pt'>100.,
14400., 0.144, 14400., <o:p></o:p></span></font></p>
<p><font size=2 face="Times New Roman"><span style='font-size:10.0pt'> <o:p></o:p></span></font></p>
<p><font size=2 face="Times New Roman"><span style='font-size:10.0pt'>** LOADS<o:p></o:p></span></font></p>
<p><font size=2 face="Times New Roman"><span style='font-size:10.0pt'>** <o:p></o:p></span></font></p>
<p><font size=2 face="Times New Roman"><span style='font-size:10.0pt'>** Name:
Far Field Stress Type: Pressure<o:p></o:p></span></font></p>
<p><font size=2 face="Times New Roman"><span style='font-size:10.0pt'>*Dsload<o:p></o:p></span></font></p>
<p><font size=2 face="Times New Roman"><span style='font-size:10.0pt'>"Outer
Boundary Surface", P, 24.<o:p></o:p></span></font></p>
<p><font size=2 face="Times New Roman"><span style='font-size:10.0pt'>** Name:
Mud Pressure-surface Type: Pressure<o:p></o:p></span></font></p>
<p><font size=2 face="Times New Roman"><span style='font-size:10.0pt'>*Dsload<o:p></o:p></span></font></p>
<p><font size=2 face="Times New Roman"><span style='font-size:10.0pt'>"wellbore
Face", P, 20.<o:p></o:p></span></font></p>
<p><font size=2 face="Times New Roman"><span style='font-size:10.0pt'>** <o:p></o:p></span></font></p>
<p><font size=2 face="Times New Roman"><span style='font-size:10.0pt'>unit is
in MPa , i considered 24 Mpa as far field stress and 20 Mpa as borehole
pressure ,also i have considered<o:p></o:p></span></font></p>
<p><font size=2 face="Times New Roman"><span style='font-size:10.0pt'>18 Mpa as
an initial pore pressure , but i didnot get reasonable results.!<o:p></o:p></span></font></p>
<p><font size=2 face="Times New Roman"><span style='font-size:10.0pt'>i will be
much appreciated for any comments.<o:p></o:p></span></font></p>
<p><font size=2 face="Times New Roman"><span style='font-size:10.0pt'>Regards<o:p></o:p></span></font></p>
<p><font size=2 face="Times New Roman"><span style='font-size:10.0pt'>Manooch <o:p></o:p></span></font></p>
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