广州市典型岩溶塌陷区岩溶发育及影响因素

Karst Development and Influencing Factors in Typical Karst Collapse Districts of Guangzhou

通过对广州市内的夏茅、金沙洲和大坦沙3个典型重大岩溶塌陷区进行调查,结合现场情况和地质背景资料,采用统计分析和对比分析等方法,深入探讨3个地区的岩溶塌陷基本特征、岩溶发育情况以及影响岩溶发育的主控因素。结果表明:1)金沙洲塌陷区的直接经济损失最高,大坦沙塌陷区受影响人数最多,而夏茅塌陷区受影响程度则相对较小;2)覆盖型灰岩是引起3处塌陷的主要物质基础,各地岩溶在纵向上的规律及溶洞的发育各具特点,其中夏茅塌陷区岩溶发育程度为强发育,其余两地为中等―强发育;3)3个地区地质断裂普遍发育,断裂构造控制着岩溶发育的方向,断裂切割使岩石破碎,增加地下水与可溶岩的接触面积,同时地下水的作用是岩溶发育的主导因素,影响着岩溶发育的规模和大小,在水动力条件较好的地段,岩溶相对发育。

Geological disasters, karst development characteristics and karst controlling factors were studied in three typical karst collapse areas（Xiamao, Jinshazhou and Datansha） in Guangzhou City. Through field investigation in the three areas and collecting the related geological background information, by using methods such as statistical analysis and comparative analysis, the following understanding can be recognized. 1） The highest direct economic losses caused by geological disasters were in Jinshazhou and the largest amount of people affected by the disasters was in Datansha, while the impact of those in Xiamao was relatively small in view of the size and extent of the geological disasters; 2） Covered limestone was the main material basis of the collapse and longitudinally karst development showed different characteristics in different areas. Karst development in Xiamao was in a strong degree, while that in the other two areas in medium-strong degree; 3） Geological faults in the three areas developed commonly, faults controlled the direction of karst, and fractures cutting the rock crushing and increasing the contacting area between groundwater and soluble rock, as the role of karst groundwater was the dominant factor affecting the scale and size of karst. The better the conditions of hydrodynamic was, the more the karst development degree would be.