Three-Dimensional Elastoplastic Numerical Simulation of Excavation and Support Processes for the Underground Powerhouse of the Shuibuya Hydroelectric Project

摘要

When the underground cavern is excavated, the initial ground stress is released and re-adjusted, thus inducing the deformation of surrounding rock masses. Behaviors of partial rocks around the cavern may turn from elasticity to plasticity, and then the damage zones could be resulted in. In this study, the three dimensional numerical model of the underground powerhouse of Shuibuya hydroelectric project was firstly established based on the results of geological investigation. To improve the accuracy of simulation, the initial ground stress field and rock mechanics parameters were adopted by considering the in-situ monitoring data. Then, the detailed construction processes, including the replacement of soft rock, excavation as well as support, were numerically simulated. Based on the modeling results, the distribution and evolution of stresses, displacements and plastic zones around the cavern were analyzed and the global cavern stability is assessed. Finally, the cavern support systems were optimized by multi-objective procedure.