洞径和覆土厚度对强夯法加固岩溶地基设计参数影响研究

Study on influence of cave diameter and covering thickness on parameter design of dynamic compaction for foundation in karst area

强夯法是处理岩溶地基溶洞常用的方法。然而现有研究主要针对具体工程进行分析,所得的结果有所限制。本文采用有限元软件Abaqus对岩溶地基进行强夯数值模拟,分析了洞径和覆土厚度对溶洞顶板的竖向位移和最大拉应力的影响。结果表明:岩溶顶板的竖向位移和最大拉应力与上覆土层厚度呈负相关,与溶洞半径呈正相关。随着上覆土层厚度的增加,溶洞顶板的竖向位移与夯击次数之间的关系会由线性变化转向非线性变化,即溶洞顶板竖向位移的增量会随着夯击次数的增加而增加。随着溶洞半径的减小,将溶洞顶板击穿时所需的夯击能相应增加。

The dynamic compaction is commonly used to deal with foundation in karst area.The existing research mainly analyzes specific projects,and the applicability of the results is limits.The finite element software Abaqus was used to perform numerical simulation on dynamic compaction for foundation in karst area.The influence of cave diameter and covering thickness on the vertical settlement and maximum tensile stress of cave ceiling is analyzed.The results show that the vertical settlement and maximum tensile stress of the karst ceiling are negatively correlated with covering thickness,and positively corrected with the cave diameter.As the covering thickness increases,the relationship between the vertical settlement of cave ceiling and the number of drops will change from linear to nonlinear,which means that the increment of vertical displacement will increase with the increase of the number of drops.As the radius of the cave decreases,the impact energy required to break down the cave ceiling increases accordingly.