武汉长江Ⅰ级阶地覆盖型岩溶塌陷成因及力学模型研究

Study on the Genesis and Mechanical Model of Karst Collapsein the First-order Terrace of Wuhan Yangtze River

岩溶塌陷已经成为制约城市发展不可忽视的问题。武汉市长江Ⅰ级阶地“上土下砂”覆盖型岩溶发育区的特点有覆盖层上部粘土层相对较薄、地下水位高且浮动明显、降雨集中且雨量大。针对该区域特定特点,分析提出武汉市长江Ⅰ级阶地岩溶塌陷的成因过程,即基岩溶蚀—砂性土漏失—土洞形成—土体塌陷。在此基础上结合“潜蚀致塌理论”和“真空吸蚀致塌理论”建立相关力学模型,给出土洞形成的临界地下水降幅以及岩溶塌陷发生的数学表达式,并对武汉市乐福园酒楼锦绣长江店北岩溶塌陷进行分析和评价,其结果与实际情况相吻合。

Karst collapse has become a problem that cannot be ignored in restricting urban development.Characteristics of the karst area of the upper and lower sands of the Yangtze River in Wuhan.The upper clay layer is relatively thin,the groundwater level is high and the floating is obvious,the rainfall is concentrated and the rainfall is large.Aiming at the specific characteristics of this area,the formation process of karst collapse in the first terrace of Wuhan Yangtze River is summarized.On this basis,the related mechanical model is established by combining the theory of collateral erosion and the theory of vacuum erosion and collapse.The mathematical expression of the critical decline of soil cavity formation and the occurrence of karst collapse is given,and the expression is used to treat the Luefuyuan restaurant in Wuhan.The analysis and evaluation of the karst collapse in the north of Jinxiu Changjiang Store are consistent with the actual situation.