深大异形基坑支撑施作与拆除技术研究

Research on Supporting and Demolition Technology of Deep and Large Size Foundation Pit Support

为了研究深大异形基坑支撑施作与拆除中的技术难点,运用数值分析软件Midas GTS模拟基坑开挖过程中地连墙、立柱、围岩的位移和应力分布情况,研究表明:第一步开挖对整个结构的受力及变形的影响最小;第二步开挖对围岩变形影响较大;第三步开挖对地连墙变形及应力影响最明显,地连墙位移最大为9.1 mm,应力最大为4312 kN/m2,且均发生在拐角位置。此外,还分析对比了深大异形基坑的支撑拆除方案,并对爆破法的工艺流程进行了研究。工程实践证明,采用爆破法拆除深大异形基坑支撑效果良好。

In order to study the technical difficulties for the construction and demolition of deep and specialshaped foundation pits,the numerical analysis software Midas GTS was used to simulate the displacement and stress distribution of the ground connection walls,columns,and surrounding rocks during the excavation of the foundation pit.Results show that the first step of excavation has the minimum impact on the stress and deformation of the entire structure;the second step of excavation has more impact on the surrounding rock deformation;the third step of excavation has the most obvious influence on the deformation and stress of the ground connection wall.The maximum displacement of the ground connection wall is 9.1 mm with the maximum stress 4312 kN/m2,both maximum values are at the corner.This paper also presents analysis and comparison of the deep and special-shaped foundation pit support demolition program and alternative blasting process.Engineering practice proves that adopting blasting method to dismantle deep and special-shaped foundation pit has good effects.