岩溶塌陷临界土洞高度的确定——以唐山市体育场岩溶塌陷为例

土洞的产生和发展是岩溶塌陷的基础和前提,临界土洞是土洞发展的最终阶段,以临界土洞为界,岩溶塌陷在时间和空间上划分为内部塌陷阶段和地表塌陷阶段。内部塌陷阶段是土洞在覆盖层土体内部的发育扩展阶段,土洞顶板土体的破坏形式类似于地下洞室洞顶围岩的破坏。根据地下洞室普氏平衡拱理论,建立覆盖层土体的天然平衡拱高度,即临界土洞高度公式,并以唐山市体育场岩溶塌陷为例,对该公式进行验证评价,计算所得塌陷的临界土洞高度与实际情况相符合,误差仅为4.3%。

DETERMINATION OF CRITICAL HEIGHT OF SOIL HOLES OF KARST COLLAPSE—&mdash|KARST COLLAPSE CASE FROM TANGSHAN PALAESTRA

The occurrence and development of soil holes is the base and precondition of karst collapse, while the critical soil-hole is the final phase of its development. Whole process of the karst collapse associated with the soil hole can be divided into two phases in term of time and space: inter-collapse phase and surface-collapse phase. The inter-collapse phase is the developing and enlarging process of soil-hole in overlying soil, and the failure of overlying soil above the soil-hole is similar to the failure of apical plate surrounding rock of underground caverns. Therefore, based on the equilibrium arc theory of М·М·Протодьяконов, the critical height of limit equilibrium arch of overlying soil, which is the critical height of soil-hole, can be determined. A case study for the karst collapse in Tangshan Palaestra, Hebei Provinces shows a good matching between calculated critical height and observed critical height with an error of 4.3%.