水位变动及降雨入渗联合作用对岩溶地面塌陷的影响分析

摘要

To analysis the joint action of water level fluctuation and rainfall on the influence of karst ground collapse ,this paper took Lujia street karst ground collapse in Wuhan city as an example ,and proposed a model for the region of karst ground collapse pressure under negative pressure .It also calculated the decline of water level and rainfall under the joint action of collapse resistance coefficient by using GeoStudio software SEEP/W and SIGMA/W module .Different rainfall , water level fluctuation were considered .It chose the mutagenicity and plentiful average water level of Yangtze river water level (Wuhan) ,the results showed that the longer the greater rainfall intensity ,the greater the displacement of the soil holes ,and joint under the action of rainfall in the Yangtze river supplies displacement is larger ,the reason could be that as the increased permeability of rock mass lowered the mechanical property ,displacement and stress distribution in differ-ent time can change it from underground erosion to osmotic pressure and gravity type ,therefore the main reason should be the rainfall and the Yangtze river water level fluctuation which change the internal erosion osmotic pressure .%为了预测地区岩溶塌陷的模式及可能性 ,以武汉市陆家街岩溶地面塌陷为研究对象 ,选择多年长江武汉关枯水期和丰水期的平均水位 ,借鉴库伦土压力理论 ,建立类黏性土承压变负压的圆坛型岩溶塌陷预测模型 ,计算其在水位下降与降雨联合作用下的抗塌系数进行初步评价 ,并进一步采用GeoStudio软件的SEEP/W和SIGMA/W模块建立降雨、地下水水位升降-应力应变数值耦合分析模型 ,研究在不同降雨强度和持续时间下土洞的发展过程.结果表明降雨时间越长 ,降雨强度越强 ,土洞位移越大 ;在长江补给联合降雨作用下的位移较大 ,通过不同时间位移和应力分布可以得到其致塌模式为潜蚀 -渗压-重力型 ,成因机制主要为降雨及长江水位变化引起的潜蚀渗压作用.