基于极限平衡法的砂土中条形基础极限承载力计算方法  

Ultimate bearing capacity analysis of strip footing on sand based on the limit equilibrium method

作　　者：赵志峰[1] 马青 方舟 Zhao Zhifeng;Ma Qing;Fang Zhou(College of Civil Engineering,Nanjing Forestry University,Nanjing 210037,P.R.China)

机构地区：[1]南京林业大学土木工程学院,南京210037

出　　处：《土木与环境工程学报（中英文）》2020年第3期10-16,共7页Journal of Civil and Environmental Engineering

基　　金：国家自然科学基金(51508279)。

摘　　要：通过理论计算确定浅基础的极限承载力是岩土研究的基本课题。由于推导中对滑动面以及承载力系数间的关系假定不同,已有理论计算出的承载力系数的数值并不完全相同。根据极限承载力分析的经典理论模型,采用极限平衡法力矩平衡条件,推导出砂土中条形基础的极限承载力计算公式,并整理得到承载力系数Nq和Nγ的表达式。与已有常用计算方法相比,推导出的承载力系数Nq和Nγ的计算公式相互独立,避免了承载力系数相互影响的不足,并减少了计算的不确定性。为验证公式的准确性,将计算结果与极限分析法的理论解答以及文献中的试验结果进行对比,结果表明,相比几种经典理论,用该公式计算出不同内摩擦角时的系数Nγ与极限分析法的计算值更加接近;用该公式计算出的极限承载力与室内试验实测的承载力也更加接近。Ultimate bearing capacity analysis of shallow foundations has been extensively studied by geotechnical scholars.Since different hypotheses exist in the slip surface and relationship between bearing capacity factors,the value of bearing capacity factors is not same depending on the theory used.Based on the classical analytical model,a limit equilibrium method of moment equilibrium is used to deduce the bearing capacity formula of strip footing on sand,and the equations of bearing capacity factors Nq and Nγare given.Compared to commonly used theoretical models,the equations of factors Nq and Nγare independent thus avoid the interplay of two factors and reduce the uncertainty in calculation.In order to verify the accuracy of the equations,the calculation is compared with the theory solution of limit analysis and laboratory test results in literature.Results indicate that the Nγvalues calculated by the proposed equations of different internal friction angle are closer to solution of limit analysis than other theoretical models.Furthermore,the bearing capacity calculated by equations in this paper shows good agreement with the data of laboratory test.

关 键 词：极限承载力 砂土 条形基础 极限平衡法 承载力系数 

分 类 号：TU447[建筑科学—岩土工程]