非对称开挖砂性土基坑刚性支护结构解析解  

Analytical Solution for Rigid Retaining Structure Under Asymmetric Excavation in Cohesionless Soil

作　　者：范晓真 许海明[2] 徐长节[1,3] 方焘[3] 谭勇[4] FAN Xiaozhen;XU Haiming;XU Changjie;FANG Tao;TAN Yong(Research Center of Coastal and Urban Geotechnical Engineering,Zhejiang University,Hangzhou 310058,China;Sinew Group Co.,Ltd.,Zhejiang University,Hangzhou 310058,China;School of Civil Engineering and Architecture,Jiangxi Province Key Laboratory of Geotechnical Engineering Infrastructure Security and Control,East China Jiaotong University,Nanchang 330013,China;Department of Geotechnical Engineering,Tongji University,Shanghai 200092,China)

机构地区：[1]浙江大学滨海和城市岩土工程研究中心,杭州310058 [2]浙江大学新宇集团,杭州310058 [3]华东交通大学土木建筑学院,江西省岩土工程基础设施安全与控制重点实验室,南昌330013 [4]同济大学地下建筑与工程系,上海200092

出　　处：《上海交通大学学报》2020年第4期397-405,共9页Journal of Shanghai Jiaotong University

基　　金：国家杰出青年科学基金(51725802);国家重点基础研究发展计划(973计划)(2015CB057801);江西省落地计划成果转化项目(KJLD4036)。

摘　　要：工程上常用的基坑支护结构设计计算方法无法适用于基坑非对称开挖的情况.针对日渐常见的非对称开挖工程,通过变形控制设计,首先引入考虑位移的非极限状态土压力理论,对作用于支护结构上的土压力进行修正.基于获得的修正土压力模式,在对支护结构进行整体受力分析的基础上,获得了可用于两侧挖深不同的单撑式刚性支护结构设计计算的解析解,并进一步分析了土体内摩擦角、支撑刚度、基坑开挖的非对称程度对支护结构安全最小插入比的影响.结果表明:经典等值梁法由于采用极限状态土压力理论,计算得到的支护结构插入比偏于不安全,且计算结果的不安全程度在土体内摩擦角较小的情况下更为严重;相对于较深侧,较浅侧插入比将对基坑的非对称开挖更加敏感;与仅按单边设计相比,该解析解可以有效节约工程造价.试验实测数据验证表明,该计算方法可用于桩土刚度差异较大情况下基坑两侧挖深不同的单撑式支护结构的设计与计算.Common design methods of retaining structure cannot be suitable in the design of asymmetric foundation pit. In view of the increasingly common asymmetric excavation, a calculation method of earth pressure considering displacement is presented to modify the mode of earth pressure acting on retaining structures. Based on the obtained earth pressure mode, the force of the whole structure system is analyzed, and the analytical solution of rigid retaining structure with bracing under asymmetric excavation is derived. The influences of the internal friction angle of soil, bracing stiffness and asymmetric degree on the insert ratio of retaining structure are analyzed. The results show that the calculated insertion ratio of classical equivalent beam method is unsafe, for the reason that this method adopts the limit equilibrium earth pressure theory. And the unsafe degree of the calculation result is more serious when the friction angle of the soil is relatively small. The insertion ratio of the shallower side is more sensitive to the asymmetric excavation than that of the deeper side. Compared with the common design method which only considers the single side, the proposed method can effectively save the project cost. The verification of the test data shows that the presented solution can be used for the calculation and design of single-strut retaining structure under asymmetric excavation.

关 键 词：基坑 非对称开挖 土压力 解析解 插入比 

分 类 号：TU470[建筑科学—结构工程]