坑底软土夹层较薄基坑以最下层支点为轴心的滑动隆起研究  

Circular Sliding Heave Stability Analysis Based on the Lowest Bracing for Deep Excavations with Thinner Soft Interlayer

作　　者：李永华[1] 叶美娇 

机构地区：[1]南昌大学建筑工程学院,南昌330031

出　　处：《结构工程师》2016年第5期186-192,共7页Structural Engineers

摘　　要：2012版《建筑基坑支护技术规程》对于锚拉式、内支撑式支挡结构,新增了当坑底以下为软土时,尚应以最下层支点为轴心的圆弧滑动模式验算基坑抗隆起稳定性的规定,并给出了解析解计算公式,该公式对基坑设计嵌固深度影响很大,大大增加了基坑支护造价。对坑底存在软土夹层基坑进行了有限元分析,得出了标准荷载作用下基坑位移变形云图、极限状态下基坑破坏机理的总位移增量云图。结果表明:软土夹层厚度较小的基坑,以最下层支点为轴心的圆弧滑动模式验算增加的嵌固深度,对于基坑位移影响较小、对破坏机理有一定程度的影响,只要有限元稳定安全系数满足规范要求,可以不进行以最下层支点为轴心的滑动模式验算。When soft clays existed at the bottom of deep excavations,the national technical Specification for Retaining and protection of building Foundation Excavationspublished in 2012 suggested that circular sliding modes checking based on the lowest bracing were performed for the anchored and inner bracing structure,and the corresponding analytical Solution were given,which increased the embedded depth and the cost of foundation excavations. The horizontal displacements and failure mechanisms of deep excavations with thin soft soil interlayer are analyzed by FEA methods. It is pointed out that the increased embedded depths have little influence on displacement deformation,but affect the failure mechanisms to some extent. As long as the safety factor of stability meets the code requirement,It doesn＇t need to checking of stability against heave by circular sliding mode based on the lowest bracing.

关 键 词：基坑 最下层支点 圆弧滑动 抗隆起 嵌固深度 

分 类 号：TU473[建筑科学—结构工程]