考虑土体有限宽度的邻近建筑基坑土压力计算方法

Calculation Method of Earth Pressure in Adjacent Building Foundation Excavations Considering Finite Soils

摘要:

基于极限平衡法建立土体受力平衡方程，得到有限宽度土体土压力理论解答，然后研究了土体宽高比、土体黏聚力、土体内摩擦角、墙土摩擦角等因素对土压力的影响规律，最后通过分析影响土体破坏夹角的关键因素得到墙后土压力简化计算公式。结果表明，在土体有限宽度条件下，同等高度处土楔体前后受力基本相同，土体内摩擦角对土压力的影响较大，土体黏聚力和墙土摩擦角对土压力的影响不大。土体破坏夹角大致在朗肯与库伦计算角度之间变化，墙土摩擦角、土体内摩擦角对滑裂面夹角及有限土压力计算范围均有显著影响。

关键词:基坑工程;邻近建筑基础;有限土体;土压力;土体破坏夹角

Abstract:

Based on the limit equilibrium method， force balance equations of the soil were established to derive the theoretical solution of soil pressures for soils with finite width. Then， the effect of factors， such as the width-height ratio of the soil， soil cohesion， internal friction angle of the soil， and wall-soil friction angle on soil pressure， was investigated. By analyzing the key factors affecting the inclination angle of soil failure， a simplified formula for calculating the soil pressure behind wall was developed. The results indicate that under the condition of the finite soil width， the forces on the front and back of soil wedges at the same height are basically the same. The internal friction angle of the soil significantly influences the soil pressure， while the impact of the soil cohesion and wall-soil friction angle is relatively minor. The inclination angle of soil failure varies approximately between the angles calculated by Rankine and Coulomb theories. Moreover， the wall-soil friction angle and the internal friction angle of the soil have significant effects on the sliding surface angle and the calculation range of finite soil pressures.

Key words:excavation engineering;adjacent building foundation;finite soils;earth pressure;inclination angle of soil failure