【摘要】 水电站地下厂房岩体洞室具有高边墙、大跨度和长轴线的特点。通过进行大量的数值模拟工作,研究这类长轴线(线长度为300～400m)大型岩体地下洞室在不同地震动幅值的一致激励和行波激励作用下的动力非线性响应。数值计算中,洞室岩体采用弹塑性损伤本构模型,同时考虑几何大变形非线性效应。对比分析一致与非一致2种地震动输入情况下该岩体洞室的动力响应。研究结果表明,对于具有同一频谱特性的地震动而言,地震动幅值对于地下洞室地震响应起决定性作用;当地震动幅值较小时(地震动幅值<0.1g),地震动行波效应对地下洞室的地震反应影响不大;当地震动幅值较大时(地震动幅值>0.2g),地震动行波效应会显著增加地下洞室的损伤破坏。因此,在进行类似的地下岩体洞室设计和地震动安全评价时,对于建在烈度较低区域的岩体地下洞室,可以不考虑地震动行波效应的影响,而对于建在烈度较高区域的岩体地下洞室,则应考虑地震动行波效应的影响。更多还原

【Abstract】 The main features for this kind of rock cavern in a hydraulic power station are high walls,large span and long axial-length,the axial length of this kind of underground rock cavern is mainly ranging from 300 to 400 m.In order to study the influence of wave passage effect on the dynamic non-linear response of underground rock cavern under uniform and wave-passage seismic excitation,separately,a great many 3D nonlinear finite element numerical simulations are conducted by considering three different amplitudes of seismic motions.The damaged plasticity model is adopted for the rock mass.Geometric nonlinearity is also considered in each simulation.For a given seismic motion with specified frequency-spectrum features,the results show that:(1) seismic response of the cavern mainly depends on the amplitude of the seismic motions;(2) As the amplitude of seismic motions is small(for example,the peak ground acceleration is less than 0.1 g).The wave passage effect has no negative impact on the underground cavern,and the wave passage effect can be ignored.(3) However,as the peak ground acceleration is greater than 0.2 g,the wave passage effect dramatically aggravates the failure of underground cavern,which indicates that the wave passage effect should be considered once the rock cavern is built in regions with highly seismic activity.更多还原