Numerical Simulation and Evaluation of Construction Process on Large-scale Underground Plants

According to main construction program of underground plants, a numerical analysis method for the second development based on FLAC^3D is used to dynamically simulate the effect of excavation and anchorage of a large-scale underground caverns of a hydropower station. Firstly, a very complex whole model and excavation model are built on the basis of construction program and excavation sequence, then some indexes such as distribution and volume of damage zones, plastic dissipated energy, the second stress field and displacement field are used to analyze comparatively the results between gross caverns and anchored caverns. The results show that solid element with 8-node-hexahedron simulating surrounding rock, cable structure element simulating anchor bar and anchor cable, thin-layer solid element simulating concrete liner could reasonably reflect factual mechanism of excavation by stages. After anchorage, stress state, deformation characteristic, distribution of damage zones and dissipated energy have been greatly improved which indicates the anchorage program are reasonable, and anchorage effect achieves a good simulation and realization.