考虑层状岩体各向异性强度的地下厂房稳定分析

针对层状岩体的各向异性强度特征,基于带拉伸截止限的摩尔库伦准则,建立了综合考虑岩体和层面强度的各向异性强度准则,并且还考虑了岩体损伤对其强度的影响,给出了该强度模型的有限元实现方法,并据此专门编写了相应的Fortran有限元程序。将该模型应用于某水电站地下厂房三维有限元开挖计算中,研究了层状岩体各向异性强度对地下厂房围岩稳定性的影响。研究结果表明:与各向同性强度准则相比,考虑层状岩体各向异性强度后洞室围岩的应力和变形分别增加了1.4 MPa和20 mm左右,总的破坏量增加了8.7%。与现场监测数据的对比表明,考虑层状岩体各向异性强度进行地下洞室围岩稳定性分析更加合理。

Stability analysis of underground powerhouse considering anisotropic strength of layered rock mass

In view of the anisotropic strength characteristics of layered rock mass, an anisotropic strength criterion considering the strengths of rock mass and layer plane was established based on the Mohr-Coulomb criterion with tension cut-off, and the influence of rock mass damage on its strength was also considered. The finite element iteration method of the model was discussed in detail, and Fortran finite element program was profiled accordingly. The proposed model was adopted in the excavation calculation of the underground powerhouse of a hydro power station to study the impacts of anisotropic strength of layered rock mass on the stability of surrounding rock of underground powerhouse, and the following conclusions are drawn: (1) compared with the isotropic strength criterion, the stress and deformation of the surrounding rock calculated by the proposed model increases by 1.4 MPa and 20mm respectively, and the total damage volume increases by 8.7%; (2) compared with the field monitoring data, the stability analysis results considering the anisotropic strength of the layered rock mass is more reasonable.