软黏土中坑中坑式抗隆起稳定安全系数计算  

Calculation Method of Safety Factor of Heave-resistant Stability of Pit-in-pit Braced Excavations in Clay

作　　者：李惠霞 何鑫龙 繆广吉 周宏伟 林上顺 LI Huixia;HE Xinlong;MIAO Guangji;ZHOU Hongwei;Lin Shangshun(School of Civil Engineering,Fujian University of Technology,Fuzhou 350118,China;China Railway Second Engineering Bureau No.3 Engineering Co Ltd,Chengdu 610041,China;College of Civil Engineering,Fuzhou University,Fuzhou 350116,China)

机构地区：[1]福建工程学院土木工程学院,福建福州350118 [2]中铁二局第三工程有限公司,四川成都610041 [3]福州大学土木工程学院,福建福州350116

出　　处：《土木工程与管理学报》2021年第1期66-71,共6页Journal of Civil Engineering and Management

基　　金：国家自然科学基金(41572253)。

摘　　要：坑中坑的开挖会明显降低基坑的抗隆起稳定性,目前的基坑抗隆起稳定分析方法基本没有考虑坑中坑的影响,导致基坑设计偏于不安全。在不同的参数影响下,坑中坑式基坑存在三种不同的破坏模式。对传统的圆弧滑动法的假定圆弧面进行改进,通过移动圆弧面的圆心,分别构建不同破坏模式下对应的圆弧滑动面。根据圆弧滑动面的特征,全面搜索得到最危险的滑动面,从而确定坑中坑式基坑的抗隆起稳定安全系数。将该方法与强度折减有限元法进行对比,通过算例分析内坑宽度及深度、内外坑间平台宽度、软土层的不排水抗剪强度对基坑抗隆稳定性的影响。发现改进的圆弧滑动法计算得到的抗隆起稳定安全系数与强度折减有限元法基本吻合。Excavating pit-in-pit will decrease the basal heave stability of outer pit.The influence of pit-in-pit on basal heave stability analysis has not been considered in existing research,which will lead to the insecurity design of pit.There are three kinds of failure modes of pit-in-pit excavation under the influence of different parameters.The traditional circle sliding surface has been improved by moving the center of circle.The circle sliding surface under different failure modes has been established.The most dangerous sliding surface is searched by the feature of sliding surface of pit-in-pit to calculate the factor of safety of basal heave stability.We compare the improved circle sliding method with finite element method based on reduced shear strength technique and get the influence of width and depth of inner pit,spacing between inner and outer pit and undrained shear strength of clay on the basal heave stability.The factor of safety calculated by improved circle sliding method is consistent with the result calculated by FEM.

关 键 词：坑中坑 抗隆起稳定 安全系数 圆弧滑动法 

分 类 号：TU447[建筑科学—岩土工程]