岩溶塌陷的致塌力学模型研究——以泰安市东羊娄岩溶塌陷为例

Study on mechanical model of karst collapse:a case of karst collapse in Dongyanglou Village,Tai'an City

2003年5月泰安市东羊娄村发生大型岩溶塌陷地质灾害,仅塌陷坑面积就达750m2。经调查研究,真空吸蚀致塌和重力致塌是该岩溶塌陷形成的致塌力学机制,致塌力主要为覆盖层土体自身重力和地下水快速下降过程中形成的真空负压吸蚀力。根据岩溶塌陷形成机理的分析结果,分3部分建立了岩溶塌陷的致塌力学综合模型,即基于普氏天然平衡拱理论的土洞极限平衡高度公式、基于极限平衡理论的桶状塌陷坑形成判别公式和基于莫尔-库伦强度理论的漏斗状塌坑形成判别公式,经东羊娄村岩溶塌陷后验分析,计算结果与岩溶塌陷的实际情况基本吻合。

On May 31, 2003, a very big karst collapse with an area of 750 m^2 occurred in farmland east of Dongyanglou Village, Tai＇ an City, Shangdong Province, which damaged the farmland and caused very serious soil loss. According to geological investigation, the deadweight of cover - layer soil and differential atmospheric pressure caused by groundwater level falling were the primary collapse forces. In this paper, based on the equilibrium arch theory, the limiting equilibrium theory and the Mohr - Coulomb strength theory, the collapse mechanical model, which contains the height expressions of soil - hole, the discriminant of column shaped collapse pit and the discriminant of cone shaped collapse pit, was established. Meanwhile, an evaluation of Dongyanglou Village karst collapse Was completed using this collapse mechanical model, and the results show that the model is in accord with fact.