Abstract: The saturated hydraulic conductivity of rock and soil mass in colluvial landslide is uncertain, and it is an important parameter for the saturated-unsaturated seepage analysis. It is of great significance to carry out the seepage deformation analysis of reservoir bank landslide considering the spatial variability of saturated hydraulic conductivity. In this study, the Baishuihe landslide in the Three Gorges Reservoir Area is investigated as a case. The spatial variability characteristics of the hydraulic conductivity, which is obtained by the surface nuclear magnetic resonance technology (SNMR), are analyzed in detail. The vertical fluctuation range of the hydraulic conductivity is obtained by using the semi-variation function, and a non-stationary random field model of hydraulic conductivity is established. The non-intrusive stochastic finite element method is adopted to carry out the fluid-solid coupling simulation of the uncertain model and the deterministic model under the two working conditions of reservoir water level fluctuation. The seepage field, deformation characteristics and their differences between the two models are analyzed. The results show that, compared with the determinate model, the hysteresis of pore pressure change in the uncertain model is more obvious, and the overall deformation is greater under the condition of reservoir water falling. If the non-stationary spatial variation of the hydraulic conductivity of the sliding body is neglected, the actual deformation of the landslide will be underestimated.

Key words: spatial variability, saturated hydraulic conductivity, reservoir water level fluctuation, unsaturated seepage-stress coupling, non-intrusive stochastic finite element method