Studies on Three-Dimensional Stability Analysis Procedure in which the Residual Factor is Incorporated

对物理矿物学性质变化较大的滑坡土进行了强度测量试验，得到了滑坡土的强度参数c和φ，用于稳定性分析。在此基础上，研究并提出了考虑残余因素的三维稳定性分析方法。在c -φ图中，将强度c = 37.5kN/ m2, φ = 35.0°处的小区域与正常固结强度接近，给出了强风化破碎泥岩的峰值强度带。正常固结强度和残余强度参数分别在φ = 23 ~ 30°和φ = 9 ~ 17°范围内。对于含粉砂颗粒较多、粘粒含量低于20%的土体，强度由峰值状态明显下降到残余状态。强度折减随优先取向粘土矿物总含量的变化呈凸曲线。根据滑坡土中矿物的总量将滑坡土的应力-位移曲线划分为4种类型。在所提出的分析程序中，精确地计算了沿滑移面作用的平均抗剪强度参数，并验证了其小于二维分析计算的参数，从而可以在整个滑移面上清晰地表达滑移处调动的峰值强度和残余强度的每个域。为合理有效地进行滑坡治理工作提供了理论依据。

Strength measurement tests were carried out on landslide soils which showed a considerable variation in physical and mineralogical properties in order to obtain the their strength parameters c and φ for stability analysis. Then the three-dimensional stability analysis procedure, in which the residual factor was incorporated, was examined and proposed.The peak strength zone for strongly weathered and fractured mudstones was given by drawing the small area that reaches from the strength of c = 37.5kN/m_2 and φ = 35.0° close to the normally-consolidated strength in the c -φ figure. The parameters of normally-consolidated strength and residual strength were within the range of φ = 23 〜 30° and φ = 9 〜 17°, respectively. A fall in the strength from the peak to the residual state was clearly observed for the soil containing a large amount of silt and sand particles, and clay fraction below 20%. The variation of the strength reduction versus total contents of preferred-oriented clay minerals was expressed as a convex curve. Stress-displacement curves of landslide soils were classified into 4 types based on the total amount of minerals in soil.In the proposed analysis procedure, the average shear strength parameter acting along the slip surface was calculated precisely and was verified to be smaller than the parameter calculated by the two-dimensional analysis, and then each domain of both the peak and residual strengths mobilized at the slide could be expressed clearly on the whole slip surface area. This procedure will be helpful in rational and effective control works for landslide.