广东几种典型斜坡类地灾体的电性结构特征分析及物探解释方法研究

Analysis of electrical structure characteristics and geophysical exploration interpretation methods of several typical slope disaster-like bodies in Guangdong

针对近年来广东省内出现的地质灾害发生数量呈日益加剧的现象,为提高物探在地灾勘查中的应用效率,这里以“十三五”期间广东省内的地灾勘查成果资料为基础素材,对广东省内的几种典型斜坡体的电性结构以地质-物性模型方式进行了实例分析研究,归纳了其要点,研究结果表明:花岗岩型斜坡体风化层的电性结构分层可分出2个~3个物性界面层,中微风化层之间普遍没有明显的物性界面,基岩与上覆风化层之间普遍存在梯度变化的物性分界面;沉积岩、变质岩型斜坡风化层与下伏基岩之间,普遍存在一处高低阻截然变化接触的物性分界面;构造成因型不稳定斜坡体中软弱结构面在电性结构面上,一般以低阻带、梯度带、高低阻过渡带等形式出现;广东省内的斜坡构造中的物性分界面(高低阻截然过渡带、梯度带等)往往与地质分界面(风化带、滑动面、断裂面、岩性分界面、层理面等)相吻合。这里的研究成果,可为斜坡灾害的破坏机理、演化过程、灾情监测预警、灾后治理、物探方法选择及成果解释等后续研究工作提供参考。

Given the increasing number of geological disasters in Guangdong Province in recent years,in order to improve the application efficiency of geophysical exploration in geological disaster exploration,this paper takes the geological disaster exploration results in Guangdong Province during the"13th five-year plan"as the primary material,analyzes and studies the electrical structure of several typical slope bodies in Guangdong Province in the form of geological physical model,and summarizes its key points.On this basis,Combined with the author's own work experience for many years,a set of geophysical exploration interpretation methods are formulated through targeted research.The results show that the electrical structure of the weathered layer of granite type slope can be divided into 2~3 physical interface layers,there is generally no apparent physical interface between the medium and slightly weathered layers,and there is generally a gradient physical interface between the bedrock and the overlying weathered layer;There is a physical interface between the weathered layer of sedimentary rock and metamorphic rock slope and the underlying bedrock,where the high and low resistances change sharply;The weak structural plane in the tectonic unstable slope generally appears in the form of low resistivity zone,gradient zone,high and low resistivity transition zone on the electrical structural plane;The physical interface(high and low resistivity sharp transition zone,gradient zone,etc.)in the slope structure in Guangdong Province is often consistent with the geological interface(weathering zone,sliding surface,fault surface,lithologic interface,bedding surface,etc.);Establish physics-Geological model→anomaly determination→anomaly classification and class by class/interpretation→qualitative interpretation→quantitative interpretation→geological interpretation→put forward the location and technical requirements of the verification project→physical property measurement,supplement and collect data,and do further interpretation of the geophysical exploration interpretation method process,which can achieve good results in many practical work applications,and the results are convenient for Party A's personnel to use directly.The research results of this paper can provide a reference for the following research work,such as the failure mechanism,evolution process,disaster monitoring and early warning,post-disaster management,geophysical exploration method selection,and results interpretation of slope disasters.