湖北武汉白沙洲隐伏岩溶区地质结构与岩溶塌陷分类

Types of geological structures and mechanism of karst collapses in Baishazhou,Wuhan City of Hubei Province

武汉市可溶岩大多隐伏于第四系土层及白垩—古近系红层下部,可溶岩分布地区地质结构与岩溶地面塌陷关系密切,已发生的岩溶地面塌陷中上黏下砂地质结构占绝大部分。以白沙洲岩溶条带长江两岸为研究区,根据盖层黏性土、砂性土、软弱土、非可溶岩(红层)的上下叠置关系及地面塌陷特征,将可溶岩分布区地质结构划分为3类、5型;岩溶塌陷的实质是土体塌陷,在岩溶区地质结构研究的基础上,根据土体物理力学特征差异,受力后塌陷过程中土颗粒的运移方式,即黏土块体塌落、砂颗粒漏失、软弱土流失,系统将研究区岩溶塌陷机理分为土洞型、沙漏型、泥流型3类,同时也存在多种类型复合型岩溶塌陷。

Most of the soluble rocks in Wuhan lie in the quaternary soil layer and the lower part of the chalk-paleogene red layer,the geological structure of the distribution area of soluble rock is closely related to the karst ground collapse,most of the happened ground collapse in the stratum with the upper clay-lower sand.The study area is on the both sides of the Yangtze River along the Baishazhou karst belt,according to the thickness and the superimposed relation of overburdened clay,sandy soil,soft soil,non-soluble rock(red bed)and surface collapse,the geological structure of the solvable rocks is classified into 3 categories and 5 types.The essence of karst collapse is soil collapse,based on the geological structure and the physical and mechanical characteristics of soil,as well as the migration mode of soil particles during collapse including the clay mass collapse,sand particle leakage and the loss of soft soil,the mechanism of karst collapse is classified into three types,such as soil cavity type,hourglass type and mud flow type,and there are 2 or 3 types of compound karst collapse.