地下洞室埋深对围岩双重非线性影响的有限元分析

Finite element analyses for influence of embedded depth of an underground opening on double-nonlinearity of surrounding rockmass

分别使用小变形和大变形弹塑性有限元方法,对位于不同埋深的地下洞室围岩动态进行了计算,分析了围岩中的塑性区、位移场和应力场。当洞室埋深较小时,岩体双重非线性表现不明显,小变形与大变形方法所得结果相当接近;当洞室埋深较大时,岩体的双重非线性明显呈现而使得两种方法的结果相差较大,此时宜选择用大变形理论。

The finite-element method with small deformation formulation as well as the large deformation formulation, is used to perform elastoplastic analyses of an underground opening with different embedded depths, and investigate the plastic zones, displacement distributions and secondary stress fields in the surrounding rockmass. It can be seen that when the embedded depth is small the computations obtained from small deformation and large deformation methods are quite close to each other, but when the embedded depth is larger , there exists a distinct difference between the results of the two methods because the double-nonlinearity of surrounding rockmass acts obviously at this time , so for the latter case, the right selection is applying the large deformation theory.