摘要
根据库伦土压力理论的原始假定,库伦土压力公式最初只适用于无黏性土;基于平面滑动法的分析结果,现行国家规范中列入了黏性土的库伦土压力公式。该公式计算的土压力为负值是一个常见的现象,但现行规范和相关文献并未对此进行说明,这给使用者带来了一定的困惑。无支挡时,若黏性土边坡处于稳定状态,则无剩余下滑力,这是土压力为负值的根本原因。基于平面滑动法,笔者首次推导出了边坡破裂角的广义表达式,并建立了黏性土边坡稳定系数计算的通用公式。验证表明,黏性土边坡的稳定系数大于1时,计算的库伦土压力恒为负值;稳定系数小于1时,土压力恒为正值;稳定系数为1时,土压力为0。由此,计算黏性土的库伦土压力时,可首先根据边坡的稳定系数判定土压力的正负关系,这对支挡设计具有一定的理论意义和工程意义,可为岩土设计人员参考,并为现行规范、手册、教材修编提供依据。
Negative calculation result of active earth pressure is a special phenomenon in geotechnical engineering,which is calculated by the formula given by current national code of China. In this paper, the relevance of active earth pressureand cohesive soil slope stability is derived to interpret this phenomenon. Based on the framework of Coulomb theory, the relevance of the stability coefficient Fs and the active earth pressure coefficient Ka is proposed.Controlling variable method is adopted to analyze the influences of calculation parameters in engineering application, such as the inclination of the wall, the height of retaining wall, the angle of the internal friction of the soil, the soil cohesion, uniform load on the top of slope, inclination angle of backfill soil, friction angle between wall and backfill soil area investigated.The results demonstrate that the relationship between the stability coefficient Fs and the active earth pressure coefficient Ka is able to interpret a special phenomenon—negative calculation result of active earth pressure. In addition, general equations of the stability coefficient and the fracture angle of cohesive soil slope is established too. It is well illustrated that the method is feasible to evaluate the stability and to define the slide surface of cohesive soil slope.
作者
陈小平
何平
田茂祥
徐艳
CHEN Xiaoping;HE Ping;TIAN Maoxiang;XU Yan(Chongqing Municipal Research Institute of Design,Chongqing 400020,China;Chongqing Duan Engineering Survey Technology Consulting Co.,Ltd.,Chongqing 400020,China)
出处
《建筑结构》
CSCD
北大核心
2021年第S02期1691-1697,共7页
Building Structure
关键词
库伦土压力理论
黏性土边坡
平面滑动法
破裂角
稳定系数
Coulomb’s earth pressure theory
coesive soil slope
plane sliding method
rupture angle
stability coefficient
