水电站地下洞室群非线性地震反应数值仿真

Numerical Simulation on Nonlinear Seismic Response of Underground Caverns in Hydropower Projects

为了解水电站地下厂房洞室群非线性地震反应特点,结合某实际工程采用拉格朗日显式差分法进行数值仿真,考虑了初始地应力、分步开挖与柔性支护以及岩体材料弹塑性等影响,考察了主厂房洞室围岩的地震位移、速度、加速度等时、频域反应特征,并对围岩稳定性进行了判别。结果表明,地下岩石洞室围岩的地震反应属低频震动;地震波竖向传播时,洞室围岩壁各点的位移(或速度、加速度)反应波形基本相似,且几乎同步;地震作用不利于洞室的稳定。

To understand the nonlinear dynamic response characteristics of underground caverns in hydropower projects, the Lagrangian explicit difference method is used to simulate the seismic responses of a hydropower project, in which, the initial stress, step excavations, flexible supporting and rock elastoplastic are taken into account. The characteristics in time and frequency domain of seismic response, such as displacement, velocity and acceleration, are presented, and the surrounding rock stability is also checked. The results show that： （a） the seismic responses of surrounding rock belong to vibrations with low frequency; （b） the displacement （or velocity, acceleration） of a point in side wall of the cavern are nearly close in the time-waveform with no phase difference; and （c） the earthquake endangers the stability of caverns.