非饱和渗流基质吸力对边坡稳定性的影响

降雨入渗是致使边坡岩土体稳定性下降并最终导致崩滑地质灾害发生最为常见的环境因素。通常对边坡中地下水的影响分析采用的是经典的静水压力假定 ,并考虑适当的折减系数。本文研究了非饱和土强度随基质吸力变化的规律 ,对基质吸力影响边坡稳定性的机制进行探讨 ,并提出了相应的分析方法。运用上述方法分析了某露天矿边坡实例。结果表明 ,该方法十分有效。

THE EFFECT OF UNSATURATED SOIL SUCTION ON SLOPE STABILITY

It is evident that the rainfall′s has a remarkable effect on slope stability, but it is generally analyzed by static pore water pressure theory based on saturated soil. Actually, in most cases, the soil, especially the coarse soil and rocks, is discovered to be unsaturated or has a process from unsaturated to saturated state during rainfall. Therefore, a new slope stability analysis approach is necessary based on unsaturated soil theory. In this paper, the effect of unsaturated soil′s suction on slope stability is discussed from basic Mohr-Coulomb′s shear strength model. Based on that we suggest a modified GLE method considering suction for unsaturated slope. This method was used to an open pit mine slope and it revealed some basic laws of suction on slope stability. The slope safety factor from this new GLE method is higher than that from traditional one, but it has a bigger decrease in the process from saturated to unsaturated state and the final safety factor when the seepage being over is smaller than that from general pore water pressure theory.