某滑坡滑体土蠕变特性及长期强度研究

通过对西南地区雅砻江库区某滑坡的滑体土开展大型三轴蠕变试验,研究了其在不同围压和应力水平下的蠕变规律,并采用等时曲线法确定了长期强度。结果表明:滑体土的变形主要由三部分构成:瞬时变形、衰减变形和等速变形,前两者分别占总应变的55.0 %和30.0 %以上。滑体土的长期蠕变造成了其抗剪强度持续降低,与常规强度相比,长期黏聚力下降约19.4 %,长期内摩擦角下降约23.7 %。滑体土的蠕变特性对水库滑坡的变形具有重要影响。

Study on Creep Characteristics and Long-term Strength of Sliding-body Soil of a Landslide

Through a large-scale triaxial creep test on the sliding-body soil of a landslide of Yalongjiang reservoir area in Southwest China, the creep law under different confining pressure and stress levels was studied, and the long-term strength was determined by the isochronous curve method. The results show that the deformation of sliding soil is mainly composed of three parts: instantaneous deformation, attenuation deformation and constant velocity deformation. The former two account for 55.0 % and 30.0 % of the total strain respectively. The long-term creep of sliding-body soil caused a continuous decrease of its shear strength. Compared with the conventional strength, the long-term cohesion decreased by about 19.4 %, and the long-term internal friction angle decreased by about 23.7 %. The creep characteristics of sliding-body soil have an important influence on the deformation of reservoir landslides.