基于黏土固化的桩基溶洞回填结构体研究与应用

Research and Application of Backfill Structure for Pile Foundation Karst Cave Based on Clay Solidification

桩基施工遇到溶洞时,传统工艺主要有钢护筒跟进、注浆、回填混凝土、回填片石+黏土等,但这些工艺有的造价较高,有的处理效果有限。为解决经济性和处理效果之间的矛盾,创新性地提出将壳状结构体回填至桩孔工艺。该结构体利用黏土固化和挤压成型原理,通过在黏土中掺入30%Na2SO4和20%CaO,使黏土快速固化,然后将固化后的黏土挤压成一种壳状结构体回填至出现溶洞的桩孔内,再反复冲击,从而达到封堵溶洞的目的。

When encountering karst caves during pile foundation construction,traditional techniques mainly include steel casing follow-up,grouting,backfilling concrete,backfilling with rubble and clay,etc.However,some of these techniques have higher costs and some have limited treatment effects.To address the contradiction between economy and treatment effectiveness,an innovative approach is proposed to backfill the shell structure into the pile hole process.This structure utilizes the principles of clay solidification and extrusion molding,by adding 30%Na2SO4 and 20%CaO to the clay to quickly solidify it.Then,the solidified clay is squeezed into a shell like structure and backfilled into the pile hole where the karst cave appears,and repeatedly impacted to achieve the purpose of sealing the karst cave.