基于COMSOL Multiphysics的重力坝渗流场与应力场耦合分析

借助COMSOL Multiphysics软件强大建模与计算功能,建立混凝土重力坝断面二维渗流场与应力场耦合模型,选择结构力学模块和描述流体流动的Richards方程模块,利用出渗面混合边界求解方法确定渗流自由面,以此研究正常蓄水情况下渗流场和应力场耦合作用的影响,并与不考虑耦合作用进行对比。结果表明:(1)考虑与不考虑耦合作用时的渗流场、应力场与位移场分布规律基本一致,但耦合作用对混凝土重力坝渗流场、应力场与位移有较明显的影响;(2)耦合作用使坝体浸润线位置稍微偏低,渗流场等势线偏向下游,坝基扬压力变大;(3)耦合作用使坝体总体应力增加,坝体上游拉应力与下游压应力增大,坝踵处的应力集中加剧。研究成果对混凝土重力坝设计具有参考价值。

COMSOL Multiphysics based coupled analysis on seepage field and stress field of gravity dam

By means of the powerful modeling and calculation functions of COMSOL Multiphysics，a 2-D seepage field and stress field coupled model for the section of concrete gravity dam is established，and then the seepage free surface is determined with the method for solving the seepage mixed boundary by selecting structural mechanics moduleplus Richards Eqution module for describing fluid flow，so as to study the coupled effect of both the seepage field and the stress field under the normal water storage condition，and then compare with the that without consideration of coupled effect. The result shows that （1） the distribution laws of the seepage field，the stress field and displacement field under the consideration or without the consideration of the coupled effect are basically consistent，but the coupled effect has a relatively significant impact on the seepage field，the stress field and displacement of gravity dam； （2） the coupled effect makes the location of the saturation line on dam body slightly lower，the equipotential lines of seepage field deflected to the downstream and the uplift pressure increased； （3） the coupled effect makes the overall stress increased，both the upstream tensile stress and the downstream compressive stress of dam body increased and the stress concentration at the dam heel exacerbated. Generally，the study result has a reference value for the design of gravity dam.