SIMULATION OF EARTHQUAKE DISASTER PROCESS OF LARGE-SCALE UNDERGROUND CAVERNS USING THREE-DIMENSIONAL DYNAMIC FINITE ELEMENT METHOD

The earthquake impact is a major external factor influencing the long term stability of underground caverns.Time-history analysis method is able to simulate the earthquake response of surrounding rock in underground caverns during earthquake disaster process.It has been proved to be an effective method to analyze the aseismic issue of underground caverns.The numerical simulation system using three-dimensional dynamic finite element method is developed to study the earthquake disaster in underground caverns.Central difference method is employed in this system to solve the problem.To enhance the solving speed,parallel procedures and hybrid Gauss point integration method are proposed in programming.Strengthening features of materials under high strain rate and damage features of surrounding rock under cyclic loading are considered.The dynamic constitutive model for rock masses is presented.It is suitable for the aseismic analysis of underground caverns.Visco-elastic boundary is adopted in artificial boundary.The spatial oblique incident method which is suitable for the aseismic analysis of underground caverns is proposed.It is able to reflect the specific incident direction,the multi-incident surfaces and the inconsistency of seismic wave.An example is given to verify the correctness of the developed system by comparing its calculation results with common software's calculation results.A case study is then conducted to simulate the earthquake disaster process of the cave-typed underground caverns at Lujichang hydropower plant.The results derived from time-history analysis indicate the reliability and practicability of the developed system.