考虑土拱效应的挡墙后土压力研究

STUDY ON EARTH PRESSURE AGAINST RIGID RETAINING WALLS CONSIDERING SOIL ARCHING EFFECTS

假设挡墙后无黏性土极限破坏时形成圆弧形主应力拱线,其中被动破坏形成大主应力拱线,主动破坏形成小主应力拱线。取破裂面呈直线,其和水平方向夹角通过土压力函数极值确定,得到考虑土拱效应的墙土界面侧向土压力系数和主应力旋转角。基于水平微分单元法,得出一种考虑土拱效应的被动土压力分布、合力大小和合力作用高度的解析式,修改了Paik考虑土拱效应的主动土压力公式。算例表明:考虑土拱效应的土压力理论比较符合模型试验的土压力分布。

Assuming the formation of a circular arch-shaped principal stresse trajectory when the noncohesivegranular backfill behind a retaining wall reaches limit equilibrium, the major and minor principal stress arches occur respectively when the backfill obtains passive and active ultimate failure. A lateral earth pressure coefficient and the rotating angle of principal stresses are deduced after considering the soil arching effect by assuming the presence of a straight failure plane, whose inclined angle towards a horizontal level is determined by the earth pressure function. The analytic formulas for the spatial distribution of passive earth pressure, the value and application height of the resultant force are solved by the differential element method （DEM）. Paik＇s formulation for active earth pressure which considers soil arching effects is further developed. The calculation examples that are conducted in this study prove the consistence between the theoretical prediction considering soil arching effects and the experimental observations in model tests.