花岗岩残积土中微裂隙对基坑安全的影响

花岗岩残积土基坑支护工程实践及位移变形观测结果表明,残积土中的微裂隙对基坑安全及变形起着决定性作用.通过对花岗岩残积土中微裂隙和充填物性状及其破坏机理的研究,总结出预防花岗岩残积土基坑开挖中的塌方宜采取相应的超前支护措施;处理花岗岩残积土的基坑塌方,宜用砂袋回填并在纵横方向打入钢管或钢筋加固回填体.在计算花岗岩残积土基坑稳定性时,应结合具体情况,以软弱面为滑动面,采用相应的稳定性计算公式进行计算.

Effect of Microfissure in Residual Soil from Granite to Stability of Pit

It shows that microfissures in residual soil are of key element to stability and deformation of pits through the engineering practice of microfissure in residual soil and the results of displacement sedimentation observation. Based on the study on properties of microfissures and fillings and the destruction mechanism, the paper sums up that it is feasible to take the advanced support patterns for defending collapse in the course of pit drilling with residual soil from granite. To cure pit collapse with residual soil from granite, what measure can be chose is to backfill with bags of sand and infiltrate steel tube or reinforce steel bar to pin up filler. According to the engineering practice, related stability formula, which takes weak structural plane as critical slide interface, can be used to calculate the stability of pit in residual soil from granite.