地应力平衡方法介绍

6.19 Enhancements to the geostatic procedure

Products: Abaqus/Standard Abaqus/CAE

Benefits: The geostatic procedure for obtaining the initial equilibrium state has been enhanced so that you no longer have to specify initial stresses that are close to the equilibrium state to obtain a solution corresponding to the original configuration.

Description: The geostatic procedure is normally used as the first step of a geotechnical analysis; in such cases gravity loads (and possibly other types of loads) are applied during this step. Ideally, the loads and initial stresses should exactly equilibrate and produce zero deformations. However, in previous releases of Abaqus the geostatic procedure did not enforce this condition. In complex problems it may be difficult to specify initial stresses and loads that equilibrate exactly. Consequently, the displacements corresponding to the equilibrium solution might be large unless a special procedure is used to enforce small displacements.

The enhanced geostatic procedure allows you to obtain equilibrium in cases when the initial stress state is unknown or is known only approximately. Abaqus automatically computes the equilibrium corresponding to the initial loads and the initial configuration, allowing only small displacements within user-specified tolerances. The procedure is available with continuum and cohesive elements with pore pressure degrees of freedom and the corresponding stress/displacement elements. The elastic, porous elastic, Cam-clay plasticity, and Mohr-Culomb plasticity material models are supported. Although the list of supported materials includes materials that exhibit inelastic behavior, the procedure is intended to be used in analyses in which the material response is primarily elastic; that is, inelastic deformations are small.

The new enhancements are available from the Incrementation tabbed page when you create or edit a geostatic step in Abaqus/CAE. You must select automatic incrementation to access the new controls. The default settings for increment size and maximum displacement change are shown in Figure 6–6.

Figure 6–6 The Incrementation options for a geostatic step.

Abaqus/CAE Usage:

Step module:

Create Step: General: Geostatic; Incrementation

References:

Abaqus Analysis User's Manual

∙“Geostatic stress state,” Section 6.8.2

Abaqus/CAE User's Manual

∙“Configuring a geostatic stress field procedure” in “Configuring general analysis procedures,” Section 14.11.1

Abaqus Keywords Reference Manual

∙*GEOSTATIC

Abaqus Verification Manual

∙“*GEOSTATIC, UTOL,” Section 5.1.9

ABAQUS 地应力平衡

2011-03-30 14:42:12

关于地应力的平衡方法,综合了版上的一些意见,结合了自己的想法,对于初始地应力的施加,得到了e-6的效果,方法比较简单,与大家分享!

1.先施加重力荷载的作用,可以在cae中实现;

2.在inp文件中的output request中写上

*el print

s,

这样就会将施加重力荷载后的应力输出到*.dat文件中了;