考虑土石坝介质非均匀性的地震波场响应特征研究  

Study on Seismic Wavefield Response Characteristics Considering the Heterogeneity of Earth-rock Dam Medium

作　　者：宗育泉 李乾 王浩 邓闻达 Zong Yuquan;Li Qian;Wang Hao;Deng Wenda(Central Southern China Electric Power Design Institute Co.,Ltd,China Power Engineering Consulting Group,Wuhan Hubei 430071,China)

机构地区：[1]中国电力工程顾问集团中南电力设计院有限公司,湖北武汉430071

出　　处：《工程地球物理学报》2025年第2期270-276,共7页Chinese Journal of Engineering Geophysics

基　　金：中南电力设计院有限公司科技研发项目(编号:40-1A-KY202410-G101);国家自然科学基金(编号:51709015)。

摘　　要：土石坝是一种典型的土石混合介质,具有明显的非均匀性,掌握地震波在非均匀坝体中的传播特征是准确探测坝体隐患的前提。本文依据实际坝体介质的土石混合特征,基于随机介质理论,通过对随机扰动进行局部的分割与重新赋值,建立了能有效体现坝体非均匀性的土石混合介质模型;采用空间六阶时间二阶的有限差分法开展了土石混合坝体地震波场的数值模拟,分析了坝体非均匀性对有效波场的影响。研究结果表明,自相关长度与局部窗口尺寸越大,建立的土石混合坝体模型非均匀性越强;地震记录中强能量的散射波主要由瑞雷面波产生,相比于常规的随机介质,土石混合介质中散射波的能量更强,持续的时间更长;散射波对近炮点的反射纵波与转换波影响较大,对反射横波影响相对较小。Earth-rock dams are typical soil-rock mixtures with obvious heterogeneity.Mastering the propagation characteristics of seismic waves in inhomogeneity dams is the premise of accurately detecting latent hazards.In this paper,based on the soil-rock mixture characteristics of actual dams and the random medium theory,a soil-rock mixture model,which can effectively reflect the heterogeneity of dams,is established through local segmentation and reassignment of random disturbances.The numerical simulation of the seismic wavefield in the soil-rock mixture dam is carried out by using the finite difference method with second-order accuracy in time and sixth-order accuracy in space,and the influence of the non-uniformity of the dam on the effective wavefields is analyzed.The results show that the larger the autocorrelation length and local window size,the stronger the heterogeneous of the dam model.The strong energy scattered waves in seismic records are mainly generated by Rayleigh surface waves.Compared with conventional random media,the scattered wave energy in soil-rock mixed media is stronger and lasts longer.The scattered waves significantly affect the reflected longitudinal waves and the converted waves near the shot points,while the impact on the reflected shear waves is relatively small.

关 键 词：土石坝 地震波场 散射波 反射波 

分 类 号：P631.4[天文地球—地质矿产勘探]