考虑整体力矩平衡的改进不平衡推力法

Improved Imbalanced Thrust Force Method(ITFM) Considering Overall Moment Equilibrium

为了提高常用的剩余推力法的精度,通过引入比例因子确定条间力作用倾角,建立同时考虑力平衡和力矩平衡的联立方程组,求得边坡安全系数,并通过算例验证了其可靠性。研究表明:不平衡力矩和边坡安全系数均随着比例因子的变化而接近线性改变;相对于常规不平衡推力法而言,改进法求解安全系数时具有更高的精度和更快的收敛速度;在不考虑水平地震力时,条间力方向与条底滑面基本平行;考虑较大地震力作用时,条间力倾角变化主要集中发生在边坡后部的少数几个条块中。当比例因子为零时,改进不平衡推力法与常规不平衡推力法是一致的,故其可以视作常规法的扩展形式。

In order to improve the precision of conventional imbalanced thrust force method （ ITFM）, by introducing proportion coeffi- cient n, inter-slice force inclination was determined and equation set could be established to obtain the safety factor Fs, taking both force equilibrium and moment equilibrium into account. The reliability was finally verified by several examples. Researches showed that imbalaneed moment and safety factor vary near linearly when n changes. Derivation of safety factor of the method owns faster conver- gence speed than conventional ITFM, as well as better accuracy. Without horizontal seismic force, inter-slice force inclination is similar to the slip surface, hut inclination variation mainly occurs in few rear slices of the slope while taking significant seismic force into consideration. When n = 0, improved ITFM is equivalent to conventional ITFM, and consequently it could be regarded as an extension of the conventional one.