地下岩体洞室群地震响应的加、卸载响应比分析

将加、卸载响应比理论引入地下岩体洞室群地震响应分析中。以输入的地震加速度作为加、卸载，以洞室围岩的加速度作为响应，合理地确定了加、卸载响应区段。通过有限差分程序FLAC3D建立了白鹤滩水电站13号机组剖面数值分析模型，选用汶川地震波进行动力时程计算，探讨地下岩体洞室群的地震动力稳定性，研究结果表明：在100年超越概率2%的地震作用下，白鹤滩水电站地下洞室群围岩响应比峰值范围在4.05～11.52之间；结合应力及位移分析，主厂房拱顶及层间错动带C4在尾调室上游边墙出露部位的围岩均进入了非线性变形状态，但响应比在整个时程中并没有趋于无穷大，围岩没有发生失稳破坏；错动带两侧的围岩产生了一定的相对位移，会对尾调室的边墙稳定性产生不利影响。该研究方法可应用于一般地下岩体结构的地震稳定性分析中。

Loading/unloading response ratio study of seismic response on underground rock cavern group

The loading/unloading response ratio theory is introduced to analyze the seismic response of underground rock cavern group.The response region is determined reasonably by taking the input seismic accelerations as loads and unloads and cavern accelerations as response.The numerical section model of No.13 unit of Baihetan hydropower station is established by FLAC3D.With Wenchuan earthquake as input wave,the seismic stability of underground rock cavern group is discussed.The result shows that the peak value of loading/unloading response ratio is about 4.05-11.52 under 2% exceeding probability in future 100 years.The rock mass around top arch of main powerhouse and interlayer C4 in upstream wall of tailrace surge chamber are under the state of nonlinear deformation,but the loading/unloading response ratio is not infinite during the whole process,with no stability failure of rock mass.The relative displacement of interlayer has adverse effect on the wall stability of tailrace surge chamber.This research method can be used for seismic stability study of common rock mass.