基坑内土体加固对悬臂式支护结构的影响分析

Analysis of influence of soil improvement on lateral deformation and inner force of cantilever retaining structure

在软土地区采用悬臂式支护结构易造成基坑侧向位移过大,工程中常采用坑底加固措施达到减少侧向位移的目的。为了得到坑底加固土体对围护结构的影响规律,首先以弹性地基梁法为基础建立了基坑的有限元模型,利用该模型分析了坑内土体的加固深度及程度对悬臂式围护结构变形及内力的影响。结果表明,悬臂式围护结构的位移随加固深度及程度的增大而减小,而且还存在着临界加固深度及程度;悬臂式围护结构的内力受加固深度及程度的影响较小。因此,合理地确定坑内土体的加固深度及程度既能保证基坑安全,又能够节省工程造价。

cantilever retaining structure caused the large lateral deformation in soft soil region.Improvement of soil is an effective measure to decrease the lateral deformation.Based on elastic foundation beam theory,a finite element model of foundation pit is founded.The effects of soil improvement on lateral deformation and inner force of cantilever retaining structure are studied.The results show that the lateral deformation reduces with the deceases of depth and degree of improvement of soil.There are critical depth and degree in improvement of soil.The change of inner force caused by depth and degree of improvement is small.To save the engineering cost and guarantee the pit safety,it is important to reasonably decide the depth and degree of improvement of soil.