ABAQUS渗流应力耦合分析中渗透荷载施加问题探讨

渗流应力耦合问题是目前数值分析的热点之一,渗流对应力的影响主要体现在渗透荷载上,然而不同学者应用ABAQUS进行渗流应力耦合分析建模时,在水荷载边界条件施加方面出现2种个问题:定义了孔压边界后,是否还有必要施加静水压力;考虑了坝基的渗流作用,是否还需要在坝底面定义扬压力荷载。通过竖向应力平衡和孔隙静水压力平衡理论及算例对这2个问题进行分析,结果表明:在应用ABAQUS进行渗流应力耦合分析时应同时考虑静水压力和孔压边界;当不考虑坝体渗透性时,应施加扬压力,而考虑坝体渗透性时,则无需再单独施加扬压力。分析成果可为研究ABAQUS进行混凝土重力坝渗流应力耦合分析时渗流荷载和水边界条件的施加问题提供参考。

Problems of Applying Seepage Pressure in Coupling Analysis of Seepage and Stress Using ABAQUS

Coupling analysis of seepage and stress has attracted considerable attention in numerical simulation. The influence of seepage on stress is reflected in the seepage load. Nevertheless,there are two decided differences listed below when scholars deal with the water pressure and boundary conditions with ABAQUS software: whether it is necessary to apply hydrostatic pressure when pore pressure boundary is defined;and whether it is essential to define uplift pressure on dam foundation if the seepage field of foundation rock is considered. In view of this,we analyzed the two problems based on vertical stress balance and pore hydrostatic pressure balance theories as well as numeri-cal examples,and conclude that both hydrostatic pressure and pore pressure boundary should be considered when submitting coupled process of seepage and stress with ABAQUS software. Moreover, uplift pressure should be ap-plied when the permeability of dam body is not considered; but when the permeability of dam body is taken into consideration,uplift pressure is not required anymore. The results offer reference for the application of ABAQUS software to seepage-stress coupling analysis of concrete gravity dam.