非极限状态下有限土体土压力计算方法探究

发布时间：2019-01-25 19:27

【摘要】：基坑工程中有限土体土压力的计算问题因支护结构的位移控制比较严格,需要考虑非极限状态土压力理论,而以往的研究大多是关于砂性有限土体在非极限状态下土压力理论的探讨,且相关计算方法仍然是基于传统的朗肯土压力理论,事实上对于不满足半无限边界条件的有限土体,朗肯土压力理论是不适用的。对于不满足半无限边界条件的黏性土有限土体,在已有研究的基础上,对墙后梯形滑动楔形土体进行分块处理;采用水平薄层法分别对其进行分析,并考虑黏性土体内摩擦角和黏聚力发挥值以及墙土之间外摩擦角和黏聚力发挥值与位移的关系,构建在非极限状态下黏性土有限土体土压力强度的微分方程;再通过推导得出黏性土有限土体在非极限状态下的土压力强度计算公式。与实际算例实测结果对比分析表明:自填土表面至基坑一定深度范围内,计算值较实测值偏大;而在一定深度以下范围内,计算值与朗肯土压力计算值差异明显,而与实测值的符合程度较好。综合来看,所提出方法是合理可行的,可供相关设计参考。
[Abstract]:Due to the strict displacement control of supporting structure, the calculation of soil pressure of finite soil in foundation pit engineering needs to consider the theory of non-limit state earth pressure. However, most of the previous studies are about the earth pressure theory in the non-limit state of the limited sand soil, and the related calculation method is still based on the traditional Rankine earth pressure theory, in fact, for the limited soil mass which does not satisfy the semi-infinite boundary conditions, the related calculation method is still based on the traditional Rankine earth pressure theory. Rankine's theory of earth pressure is not applicable. For the limited clay soil which does not satisfy the semi-infinite boundary condition, the trapezoidal sliding wedge soil behind the wall is divided into blocks on the basis of existing research. The horizontal thin layer method is used to analyze the internal friction angle and cohesion of the clay, and the relationship between the external friction angle and cohesion and the displacement of the wall and soil is taken into account. The differential equation of the finite soil pressure strength of the clay soil under the non-limit state is constructed. Then the formula for calculating the soil pressure strength of the clay limited soil under the non-limit state is derived. The comparison and analysis of the measured results with practical examples show that the calculated values are larger than the measured values from the surface of the fill soil to a certain depth of the foundation pit. But in the range below a certain depth, the calculated value is obviously different from the Rankine earth pressure calculation value, but the agreement with the measured value is good. In a word, the proposed method is reasonable and feasible and can be used as a reference for related design.
【作者单位】：中国地质大学(武汉)工程学院;
【分类号】：TU432

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