三峡大坝蓄排水过程对岩石各向异性的动态影响研究

项目名称： 三峡大坝蓄排水过程对岩石各向异性的动态影响研究

项目编号： No.41474093

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 天文学、地球科学

项目作者： 张朝玉

作者单位： 武汉大学

项目金额： 85万元

中文摘要： 三峡大坝的岩体安全性一直是地震地质工程关注的热点问题，三峡核心地区岩体的各向异性及其时变特征反映了所承受的地应力变化，地应力的积累和释放过程伴随着大坝的蓄排水动态过程。为了获得大坝蓄排水过程对三峡岩体各向异性的影响，本项目基于三峡地震台网监测到的大量历史地震数据，提炼岩石各向异性参数及其时变效应，进行相关分析。主要是利用发生在库区及周边地区的地震事件，提取高分辨率的时变面波频散信息，选择各向异性等效模型，通过地震波的背景速度及扰动量协同反演各向异性参数，进而研判岩石的物理性质变化。

中文关键词： 三峡大坝；各向异性；面波频散；地震；反演

英文摘要： The safety of rocks of Three Gorges Dam has been being concerned by earthquake engineering geologists. The time-varying features of the rock anisotropy correspond to the alternations of surrounding stress fields. The accumulation and release of the stress refer to the processes of reservoir water storage and drainage. In order to evaluate the time-varying effects of the reservoir water storage and drainage on the anisotropy of Three-Gorges host rocks, the present study calculates the anisotropic parameters of the host rocks, based on the massive historical seismic records, and then studies the relations in between the two factors. By selecting the wave phases of the seismic events happened in the reservoir area and surrounding areas, surface waves are purified to abstract the high-resolution dispersion data. Several anisotropic models are optimized prefer to effective rock model. The stable surface-wave velocities and the perturbations are inverted to get the anisotropic parameters of the host rocks, which are used to evaluate the changes in physical properties.

英文关键词： Three Gorges;anisotropy;surface-wave dispersion;earthquake;inversion