Numerical Simulation of the 3D Landslide Stability in Three Gorges Area Based on NMR

Reliable hydrological parameters of the rock and soil in a landslide are difficult to obtain using traditional investigative and testing methodology. This affects the quality of landslide modelling and evaluation. Based on the NMR (nuclear magnetism resonance) method of water seeking combined with some other investigation methods, a 3D landslide model was established. The method for studying the landslide stability in the Three Gorges was presented. The Zhaoshuling landslide in the Three Gorges Reservoir area was chosen to determine the accuracy of the 3D modelling. The hydrological parameters of the rock and soil were obtained by NMR and from a borehole. Two aquifers were determined: the upper one is an unconfined aquifer; and two sliding zones were found. The result from NMR analysis was identical with the data obtained from the borehole. This result could supply a reliable basis for landslide modelling which conforms to actual landslide conditions. Using the FEM program to consider the interaction between seepage and stress and ANSYS, the stability of the landslide was simulated with a water level under 145 m, at 175 m and from 175 m falling to 145 m. The results show that the landslide is still in a stable state at a water level of 145 m and 175 m. The unstable area in the front region of the landslide enlarges as the water level rises. When the water level falls from 175 m to 145 m, the landslide is in a state of limited equilibrium and local deformation and damage on the posterior border of the landslide is likely to occur.