考虑渗流与蠕变耦合作用的水库滑坡变形数值分析

The deformation of reservoir landslide is mainly resulted from fluid-solid coupling. It is not occurred immediately, but gone through a long-term development and exhibiting typical rheological characteristics. In this study, the extended Burgers creep model (M-2K) was derived and extended into the three-dimensional form. The creep testing results of the landslide soil were fitted by the derived M-2K creep model and the creep model parameters were obtained. A time-dependent relationship was introduced in to the traditional fluid-solid coupling analyses, and a mathematical model of the seepage-creep coupling was derived and solved by finite element method. Taking the Baijiabao landslide in the Three Gorges Reservoir Area as an example, the numerical calculations considering the seepage-creep coupling or non-coupling were completed using this program. The results demonstrate that the three-dimensional M-2K creep model had a high fitting degree and could reflect the creep properties of the landslide soil. The finite element calculation results show that the pore pressure reduction value under the seepage-creep coupling condition was greater than that under the non-coupling condition. The displacement calculation results of the key points under seepage-creep coupling or non-coupling conditions were compared with the actual GPS displacement measurements. The evolution trend of calculated results were basically consistent with the actual monitoring results, and the displacement values of two monitoring points considering the seepage-creep coupling were larger than those without considering the coupling process and more closer to the actual value. The results show that the established mathematical model of seepage-creep coupling is reasonable and the finite element numerical solution procedure is correct. The research provides a more reasonable and accurate new way for reservoir landslide prediction.