多道瞬态面波法与微动法联合推断岩溶塌陷区覆盖层的结构和厚度分布

摘要

In order to obtain the structure and thickness distribution of the overburden layer in the typical karst collapse area in large scale,multi-channel transient surface wave method and microtremor method were used to carry out field survey in the typical karst collapse area of Dongquan commune in Liucheng country, Liuzhou city.Based on the relationship between the characteristic frequency and the thickness of the forma-tion extracted by the microtremor method,combined with the existing borehole data,the functional relation-ship between the thickness of the covering layer and the characteristic frequency is obtained and the thickness distribution of the overburden layer can be derived.The shear wave velocity distribution of the overburden layer was obtained from the dispersion characteristics of the surface wave,based on which the structural dis-tribution of the overburden layer can be derived.With the structure and thickness distribution of cover layer, four local faults or dissolution trenches in the survey area were inferred.The study shows that the structure and thickness distribution of the overburden layer can be effectively deduced by using the characteristic fre-quency of microtremor and the dispersion characteristics of the surface wave.%为了大尺度范围内获取岩溶塌陷典型调查区覆盖层的结构和厚度分布,采用多道瞬态面波法与微动法,对柳州市柳城县东泉公社幅岩溶塌陷重点调查区进行了野外观测,根据微动法提取的特征频率与地层厚度的关系,结合已知钻孔资料,得出覆盖层厚度与特征频率的函数关系,获取了覆盖层的厚度分布,根据面波的频散特性,得出覆盖层的横波速度分布,获取了覆盖层的结构分布,结合得出的覆盖层结构和厚度分布,推断出测区内发育4条断层或溶沟等局部构造.研究表明,利用微动法提取的特征频率和面波的频散特性,可以有效地推断出塌陷区覆盖层的结构和厚度分布.