饱和黏性土的总强度与基坑工程水土合算土压力分析方法  

Total Strength of Saturated Clay and Earth Pressure in Excavation by Total Stress Analysis Method

作　　者：高彦斌[1] 姚天骄 杨正园 GAO Yanbin;YAO Tianjiao;YANG Zhengyuan(College of Civil Engineering,Tongji University,Shanghai 200092,China)

机构地区：[1]同济大学土木工程学院,上海200092

出　　处：《同济大学学报（自然科学版）》2020年第9期1296-1304,共9页Journal of Tongji University:Natural Science

基　　金：国家自然科学基金(41972273)。

摘　　要：回顾了饱和黏性土总强度Su的概念以及“φ=0法”的基本原理,指出直接将三轴固结不排水强度指标ccu、φcu和直剪固结快剪强度指标ccq、φcq代入朗肯土压力公式是一种错误的分析方法,由此导致了对水土合算土压力分析方法的误解。根据两种试验的原理,推导出了采用强度指标ccu、φcu和ccq、φcq表示的总强度Su,进而依据“φ=0法”,给出了基坑开挖卸载下正确的水土合算土压力公式。结合该公式,对行业规范中采用的一些土压力计算方法进行了评述,并结合算例结果对计算分析中几种强度指标的应用进行了评价。Based on the review of the concept of total strength Su and the principle of“φ=0 method”,it is pointed out that directly substituting the strength parameters of ccu andφcu by triaxial consolidated undrained shear test,and the strength parameters of ccq andφcq by direct shear test into Rankine’s earth pressure is a uncorrected analysis method.It results in the misleading of the application of the total stress analysis method.According to the principle of the two kinds of test,the formulations of total strength Su using the strength parameters of ccu,φcu,and ccq,φcq are derived.Then,according to the principle of“φ=0 method”,correct earth pressure equations applied to unloading condition in excavation are presented.Based on the new equations,the analysis methods given in several domestic standards or specifications are discussed.Finally,different kinds of strength parameters in earth pressure analysis are evaluated with analysis examples.

关 键 词：饱和黏性土 总强度 水土合算 土压力 

分 类 号：TU471[建筑科学—结构工程]