大型地下洞室群地震动输入机制探讨

摘要

Extensive research has been conducted for the seismic response character of the underground engineering.Meanwhile less effect has been put on the seismic input mechanism in the dynamic analysis.To cover this regretful circumstance,this paper makes some discussions on this issue.A rational selection process is firstly proposed for various types of ground motion.The types include original record,modified record,and artificial simulated waves.Design ground motion reference plane (point) and artificial boundary input ground motion determining approach are then studied.A seismic input procedure is formed specifically for underground cavern complex.The seismic input mechanism is methodical and interpreted by integrating the ground motion selection process and seismic input procedure.Ultimately,demonstrations are conducted for the Baihetan underground cavern complex with proposed approaches.%当前地下工程地震稳定性分析中对地震响应规律研究较多，而对分析中地震动输入机制研究则明显不足。本文针对这一现状，对大型地下洞室群地震响应分析中的地震动输入机制进行了一定的讨论。首先提出将分析中所涉及的地震动分为指定的实测强震记录、优选的实测强震记录、人工地震波3类，分别讨论了每种地震动的选取方法，形成了一套实用性较强的选取流程。随后提出了对设计地震动基准面（点）的建议，并研究了基于基准面（点）的人工边界输入地震动量值的确定方法，形成了适用于高山峡谷地形下大型地下洞室群地震动输入方法。将上述地震波的合理选取方法和高山峡谷地形下大型地下洞室群地震动的输入方法相组合，最终形成了一套可操作性较强的高山峡谷地形下大型地下洞室群地震动的输入机制。最后以白鹤滩水电工程地下洞室群为工程实例，对本文提出的地震动合理选取方法和高山峡谷地形下大型地下洞室群地震动的输入方法进行了工程应用，表明本文的方法为工程抗震设防分析提供了优质的地震输入参数。