人工抽水引起土洞扩展条件的分析

Analysis of Expansion Condition of Soil Cavity Induced by Pumping

土洞的形成与扩展是产生覆盖型岩溶地面塌陷的前提条件之一。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。土洞周边不同的点,受抽水引起的剥落力是不同的。随着土洞的不断扩大,剥落力增大。当土洞一旦开始向外围扩展,由于剥落力越来越大,土洞呈现发展趋势。

The formation and expansion of a soil cavity is among the basic conditions of the overburden karst collapse. 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. It is indicated that the expanding condition of soil cavity is the spalling force exceeding tension strength of soil： increasing along with the continuous expansion of soil cavity, spalling forces caused by pumping water are heterogeneous around the soil cavity, so once expansion start, the soil cavity shows an accelerated developing trend because of the increasing spalling forces.