中文摘要：

为探究降雨作用下欢喜坡冰水堆积体角砾土的强度变化规律,进行了天然和4种不同降雨历时条件下的角砾土现场剪切试验,并结合土水特征曲线探讨了该类特殊土体的非饱和强度特性。降雨作用对欢喜坡冰水堆积体角砾土的抗剪强度有着显著的影响,其近似饱和时的黏聚力和内摩擦角比天然含水率情况分别降低64.3%和22.5%;降雨入渗使角砾土基质吸力迅速降低,因此在短时强降雨条件下会导致角砾土抗剪强度丧失过大,容易诱发浅层土体滑坡;建立了欢喜坡冰水堆积体角砾土非饱和黏聚力与含水率参数χ（w）的关系式,实际应用时可采用多项式函数来确定χ（w）。

英文摘要：

In order to investigate the variation in strength of the breccia soil in the Huanxipo outwash deposit under the action of rainfall, in-situ shear tests of the breccia soil are conducted under the natural condition and under four different rainfall duration conditions. The unsaturated strength characteristics of this special soil are discussed by combining the soil water characteristic curve. Rainfall has a significant effect on the shear strength of the breccia soil in the Huanxipo outwash deposit. When it is approximately saturated, the cohesion and internal friction angle are 64.3% and 22.5% respectively lower those in the case of natural water content. The infiltration of rainfall rapidly reduces the matric suction of the breccia soil, and the heavy rainfall in a short time will lead to too much loss of the shear strength of the soil, which is liable to induce the landslide of the shallow soil. The equation of the relationship between the unsaturated cohesion and the water content parameter χ（w） of the breccia soil in the Huanxipo outwash deposit is established. In practice, the polynomial function can be used to determine the parameter χ（w） .