平行竖墙间的土拱效应与侧土压力计算

本文对墙土摩擦部分发挥时平行竖墙间小主应力进行理论分析，得出土拱形状的理论表达式，并证明其为悬链线。随后比较了悬链线拱和简化的圆弧形拱的形状、墙间竖向应力分布和侧土压力系数的差别，推导了考虑土拱效应的平行墙间侧土压力计算公式。最后通过算例分析了土拱效应对土压力计算结果的影响。研究表明，不考虑土拱效应的常规方法计算的土压力偏不安全，采用悬链线拱和圆弧形拱得到的土压力分布差别很小，在实际工程中，建议可采用相对简单的圆孤形拱。

Soil arching and estimation of earth pressure on two parallel vertical walls

In this paper, minor principal stresses of the soil between two parallel vertical walls were theoretically analyzed considering the partial development of wall friction. The formula of soil arch shape was obtained, and the curve was proved to be catenary. The distribution of vertical stress between the walls and the coefficients of lateral earth pressure according to catenary arch were compared with that according to circular arch. The formula of lateral earth pressure against parallel walls considering the arching effects was derived. This study shows that the method that not considering the arching effects is not safe. It is also shown that the lateral earth pressures on two parallel walls obtained by selecting circular arch and catenary arch are almost the same, and the former is simpler and should be selected in computation.