RT模式下考虑主应力偏转的刚性挡墙地震主动土压力

依据拟静力学理论,考虑主应力偏转的影响,推导了绕墙顶转动模式(RT模式)下的地震主动土压力的计算公式。通过旋转挡土墙的解析模型,将地震问题转化为静力问题,并根据库仑土压力理论得到地震主动破裂角。在此基础上改进圆弧形小主应力偏转迹线,利用摩尔应力圆得到了RT模式下地震主动侧压力系数和水平微元土层间摩擦系数公式,提出基于微分薄层法的地震主动土压力解析式。分析了主要参数对地震主动破裂角、地震主动侧压力系数、水平微元土层间摩擦系数、地震主动土压力分布和侧向土压力作用位置的影响。将解析结果与其他土压力理论及试验数据进行对比,结果表明本文方法更为可靠。

Seismic active earth pressures on rigid retaining walls under RT mode considering rotation of principal stresses

Considering the rotation of the principal stresses, new formulae for seismic active pressures on rigid retaining walls under rotation about top (RT mode) are derived by the pseudo-static method. Through the rotation model, the calculation of seismic active earth pressures by the pseudo-static method is transforming into that of static active earth pressures, and the seismic active rupture angle is obtained by means of the Coulomb earth pressure theory. According to the Mohr stress circle and the improved circular arc trajectory of the minor principal stresses being a circular arch, the coefficients of the lateral seismic active earth pressures and the horizontal interfacial frictions are proposed under RT mode. Then based on the force equilibrium of the differential sliding backfill element, the formula for the seismic active earth pressures on the rigid retaining wall under rotation about top is obtained. Moreover, the effects of influence parameters on the seismic active rupture angle, lateral seismic active earth pressure and its coefficient, horizontal interfacial friction coefficient, resultant of the seismic active earth pressure and height of its application are discussed. And comparisons of the predicted values by the proposed method and other methods are carried out as well as model tests, and it is shown that the proposed method is more reasonable and effective than other methods.