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挡土墙后填土面为倾斜时,朗肯土压力理论应用很少。经典的各种土压力理论是基于Mohr-Coulomb强度准则得出的,没有考虑中主应力的影响。首先推导了填土面倾斜时的朗肯主动和被动土压力的计算公式;根据平面应变假设确定了中主应力σ2=ν(σ1+σ3),在此基础上推导了统一强度理论下的材料强度指标计算公式,利用该公式可将Mohr-Coulomb强度准则下的材料强度指标转化为考虑中主应力效应的统一强度理论下的材料强度指标;最后通过一算例采用正交试验设计对反映中主应力影响的中间主剪应力系数、泊松比、填土面倾角、黏聚力、内摩擦角、重度6种因素进行了敏感性分析。结果表明:影响朗肯主动土压力强度的6种因素从大到小分别为:重度、中间主剪应力系数、黏聚力、内摩擦角、倾角、泊松比;影响朗肯被动土压力强度的6种因素从大到小分别为:内摩擦角、中间主剪应力系数、泊松比、黏聚力、倾角、重度;中主应力对朗肯土压力计算结果的影响是一个不可忽视的重要因素。
After the retaining wall filling surface is tilted, Rankine earth pressure theory is rarely applied. The classical theory of earth pressure is based on the Mohr-Coulomb strength criterion, without considering the influence of the principal stress. Firstly, the formula of Rankine’s active and passive earth pressure is deduced when the filling surface is tilted. Based on the plane strain assumption, the middle principal stress σ2 = ν (σ1 + σ3) is deduced. Based on this, the material under uniform strength theory Which can be used to transform the material strength index under the Mohr-Coulomb strength criterion into the material strength index under the unified strength theory considering the effect of the main stress. Finally, an example of using the orthogonal experimental design to reflect the medium The main shear stress coefficient, Poisson ’s ratio, filling surface inclination, cohesion, internal friction angle and severe degree of the main stress affect the sensitivity analysis. The results show that the six factors influencing Rankin’s active earth pressure intensity are: heavy degree, intermediate principal shear stress coefficient, cohesion, internal friction angle, dip angle and Poisson’s ratio; the influence of Rankine’s passive earth pressure intensity The results show that the influence of middle principal stress on Rankine’s pressure is an important factor that can not be neglected Key factor.