饱和黏性土地基不排水条件下承载力计算方法  

A calculation method for the bearing capacity of saturated soil under undrained conditions

作　　者：宋二祥[1,2] 付浩 李贤杰 SONG Er-xiang;FU Hao;LI Xian-jie(Department of Civil Engineering,Tsinghua University,Beijing 100084,China;Key Laboratory of Civil Engineering Safety and Durability of the Ministry of Education,Tsinghua University,Beijing 100084,China)

机构地区：[1]清华大学土木工程系,北京100084 [2]清华大学土木工程安全与耐久教育部重点实验室,北京100084

出　　处：《岩土力学》2021年第11期2919-2924,2952,共7页Rock and Soil Mechanics

基　　金：国家自然科学基金项目(No.51778339);国家973计划课题(No.2014CB047003)。

摘　　要：针对饱和黏性土地基在相对快速加载亦即不排水条件下的极限承载力问题,指出应采用不固结不排水强度进行计算,如采用固结不排水强度指标直接计算将给出严重偏大的结果。接着给出由中国一般地勘报告中所提供固结不排水强度指标计算不固结不排水强度的公式,由此给出近似随深度线性增大的不固结不排水强度c_(u)。进而提出此种地基极限承载力的计算方法,其基本思路是采用滑移面平均深度处的c_(u)进行计算,关键技术是构建了确定滑移面最大深度的无量纲参数,通过理论分析与数值计算拟合给出简便实用的计算公式。与有限元极限分析方法的大量计算对比表明了所给无量纲参数及承载力计算方法的正确性和高精度。With regard to undrained analysis of saturated clay foundation for its ultimate bearing capacity under rapid loading, this study has proposed the calculation of the unconsolidated-undrained(UU) strength instead of employing the consolidated-undrained(CU) strength parameters directly due to overestimated results. The formula for predicting UU strength has been deducted based on the CU strength parameters referring to the reports of geological investigation, and the profile of the UU strength c_(u), found increases linearly with depth, has been built up. A calculation method for the bearing capacity of this foundation type is therefore proposed. The basic idea thereof is to use the value of c_(u)at the average depth of the slip plane in the calculation, and a dimensionless parameter,which plays the key role, is introduced to determine the maximum depth of the slip surface. The accuracy and the precision of this parameter, as well as the proposed method, has been validated via a large number of comparative calculations with the finite element limit analysis method in this study.

关 键 词：地基承载力 饱和黏性土 不固结不排水强度 固结不排水强度指标 

分 类 号：TU470[建筑科学—结构工程]