RT模式下挡土墙主动土压力的确定

Determination of active earth pressure behind retaining wall rotating about top

墙背土压力的分布情况与挡土墙变位模式、墙体位移大小密切相关。考虑位移影响的土压力分析方法是在已知墙体位移大小的情况下,才能计算墙背土压力的分布。针对RT(绕墙顶转动)模式下的挡土墙,从满足挡土墙倾覆稳定性和基底不受拉力的角度考虑,利用改进的水平层析法,建立倾覆力矩和抗倾覆力矩的平衡方程,得到了墙底位移未知情况下确定挡土墙主动土压力的一种方法。分析结果表明:墙宽有一个合理的取值区间,在区间内墙宽的土压力大致在库伦土压力和静止土压力之间;随着墙宽的增大,墙背土压力增大,倾覆力矩和抗倾覆力矩随之增大,墙底位移随着墙宽的增大而减小;墙背越光滑,则倾覆力矩越大,满足倾覆稳定所需的墙宽就越大。

The distribution of earth pressure behind the wall is closely related to with mode of rotation and wall movement. The earth pressure analysis method considering the influence of the displacement can only calculate the distribution of the earth pressure behind the wall when the displacement of the wall is known. For the retaining wall rotating around the top,considering from the aspect of satisfying the overturning stability of retaining wall and wall base can＇t be stressed,using modified horizontal layer analysis method,the equilibrium equation of overturning moment and the anti-overturning moment is established,this paper obtains the earth pressure distribution in active equilibrium state under the circumstance that the displacement of wall is unknown. The results show that the wall width has a reasonable range of values. The earth pressure is roughly between the Coulomb＇s pressure and the static earth pressure when the value of width is within in this range; With the increase of the wall width,the earth pressure increases,overturning moment and anti-overturning moment increase,and the wall bottom displacement decreases; The smoother the wall back is,the greater the overturning moment is,the wall width meeting the overturning stability requires to larger.