滑坡滑带土非饱和蠕变特性模型研究

绝大多数滑坡的失稳过程实质为非饱和蠕变过程。在Singh-Mitchell研究成果的基础上,研究了低应力水平下蠕变变形与时间的关系,将蠕变过程划分为衰减蠕变、等速蠕变和加速蠕变3个阶段,并且将基质吸力作为一种新的应力变量反映到模型中,从而建立能够反映应力-吸力-应变-时间的非饱和蠕变模型。以三峡库区千将坪滑坡滑带土为研究对象,根据非饱和三轴蠕变试验数据对模型参数进行求解,并根据参数λ1、λ2与应力水平的关系,参数B、βDR与时间关系对模型进行修正,推导了适用于非饱和土的非线性蠕变模型。采用试验数据对模型进行验证,发现该模型能够较合理地预测滑坡滑带土的蠕变特性。

Model study on unsaturated creep characteristics of landslide soils

The instability process of most landslides is non-saturated creep essentially. On the basis of research results by Singh-Mitchell, we study the relationship between creep deformation and time variable under low stress levels. The creep process can be divided into 3 stages of decayed creep, steady creep and accelerated creep. An unsaturated creep model that reflects the relation of stress-suction-strain-time is established, in which the matrix suction is considered as a new variable of the model. According to the unsaturated triaxial creep test on landslide soil collected at Qianjiangping landslide, Three Gorges Reservoir area, the model parameters are calculated, and the model are further corrected according to the relationship between the parametersλ1、λ2and stress level, and the relation between B、β_DR and time. The model is validated by experimental data and the results indicate that the model could forecast the creep characteristics of landslide soil.