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土洞的形成与扩展是产生覆盖型岩溶地面塌陷的前提,为了研究人工抽水引起的岩溶区路基塌陷的机理,用解析法分析了土洞扩展的条件,提出了剥落力的概念,认为土洞的向上扩展是剥落力大于土体抗拉强度的结果。剥落力σb是时间和空间的函数,土洞周边不同的点,受抽水引起的剥落力是不同的。土洞一旦开始向外围扩展,由于剥落力越来越大,所以土洞呈现发展趋势。当抽水使地下水位下降时,剥落力σb增大。因此,岩溶区抽水时必须控制水位降深、流量,从而最大限度地避免路基土洞和岩溶塌陷的产生。
In order to study the mechanism of subgrade collapse in karst area caused by artificial pumping, the paper analyzes the conditions of expansion of soil holes and puts forward the concept of peeling force. It is considered that soil holes The upward expansion of the peel strength is greater than the tensile strength of soil results. Peeling force σb is a function of time and space, different points around the soil hole, the pumping force caused by the peel force is different. Once the soil hole began to expand to the periphery, due to the increasing peel force, so the soil hole presents the development trend. When pumping down the water table, the peeling force σb increases. Therefore, karst area pumping water must be controlled to reduce the depth, flow, so as to maximize the avoidance of subgrade soil cave and karst collapse.