考虑堤坝介质随机性的渗漏区域地震波场特征

Leakage is the most prominent hidden trouble in the dam, if not timely detection and treatment, will seriously affect the safety of the dam. According to the characteristics of multiphase, discrete and random distribution of dam medium, basing on the multiphase discrete random medium model, this research reveal the characteristics of the seismic wave field in the seepage zone during the formation of dam seepage combining with physical experiment, numerical simulation and theoretical study. The image threshold segmentation technique is used to extract the characteristic parameters of dam media. A multiphase discrete random medium model is constructed by using the mixture of elliptic autocorrelation function and the adjacent point fusion method and predicting seismic wave field in random media by means of anisotropic finite difference numerical simulation. Expounding the change law of water content in the leakage zone during the formation of dam seepage is expounded, analyzing the dynamic characteristics of the seismic wave propagation in different water content leakage areas and establishing the relationship between water content and seismic attributes in dam seepage area. The research results can provide a scientific basis for the fine interpretation of seismic wave detection of dam leakage, and promote the development of seismic wave detection technology.

渗漏是堤坝中最为突出的隐患，如不及时探明和处理，将会严重影响堤坝的安全性。本项目针对堤坝介质多相、离散、随机分布的特点，以多相离散随机介质模型为基础，结合物理试验、数值模拟和理论研究，揭示堤坝渗漏形成过程中渗漏区域的地震波场变化特征。利用图像阈值分割技术，提取堤坝介质的随机特征参数；采用混合型椭圆自相关函数和邻点融合法，构建多相离散随机介质模型；通过各向异性有限差分数值模拟方法，预测堤坝随机介质中的地震波场响应；阐明堤坝渗漏形成过程中渗漏区域含水量变化规律，对比分析不同含水量渗漏区域的地震波场传播动力学特征，建立堤坝渗漏区域含水量与地震属性之间的关系。研究成果可为堤坝渗漏地震波探测的精细解释提供科学依据，推动堤坝渗漏隐患地震波探测技术的发展。

渗漏是堤坝中最为突出的隐患，如不及时探明和处理，将会严重影响堤坝的安全性。针对堤坝内部介质离散、随机的特征，以随机介质理论为基础，建立不同土石比例与渗漏程度的堤坝模型，分析土石比变化对散射波场的影响以及随渗漏区域含水量增加渗漏隐患波场的变化特征，研究结果表明：离散随机堤坝模型不仅能描述坝体各类介质弹性参数离散、随机的分布特征，而且能体现出各类组成介质含量百分比；随着堤坝内部石料含量增加，散射波能量逐渐减小；当渗漏区域处于坝体与基岩分界面时，通过渗漏区域不同含水量地震记录纵波信息无法分辨出渗漏隐患，根据渗漏转换波反射特征能有效的识别出渗漏隐患大致区域与渗漏严重程度，且在渗漏隐患波场特征能量较弱，从地震剖面中很难识别时，可借助其瞬时相位进行判别。