To reveal the mechanism of karst collapse induced by groundwater pumping, the authors analyse the expanding condition of soil cavity by analytical method and put forward the concept of spalling force.

• 为研究人工抽水引起的岩溶地面塌陷的机理，用解析法分析了土洞扩展的条件，提出了剥落力的概念，认为土洞的扩展条件是剥落力大于土体抗拉强度。