Study On Numerical Simulation Of Rainfall Induced Debris Flow On Slope

Slope debris flow is an important geological disasters in mountainous areas along the highway of our country, mainly controlled by rainfall. Based on the study of slope debris flow fine evolution mechanism of the National Natural Science Fund Project ""(No. 41071017), a numerical simulation is conducted in the model test results, achievements are as follows:(1) This paper analyzes the factors affecting the formation of slope debris flow, focuses on the influence of topography and water conditions on formation of debris flow on slope surface. Terrain is the controlling factor of slope debris flow occurs, which determines the form of debris flow after the occurrence of damage. Rainfall is the main role of hydrological conditions, the rainfall is the main induced factors of slope debris flow occurs, it changes the soil hydrological and geological conditions of slope, and is also the necessary condition of rainfall debris flow on slope, it not only provides a rich source for the formation of debris flow, reducing power of rain for the movement of debris flow.(2) The increase of pore water pressure is closely related with the cumulative rainfall, cumulative rainfall in the faster growth, the growth rate of pore water pressure is too small. In the experiment 5, for example, in the case of the same rainfall, rainfall duration in 8h test, the cumulative rainfall average growth rate is 12.5mm/h, the pore water pressure increases from-0.00433 Mpa to 0.0041 Mpa, the growth rate was 0.00843 Mpa. The rain lasted 4 hours in the test, the cumulative rainfall average growth rate is 25mm/h, the pore water pressure increases from-0.00619 Mpa to 0.0031 Mpa, the growth rate was 0.00919 Mpa.(3) According to the size and model test data, Using the FLUENT module in ANSYS14.5 combined with the numerical simulation of large deformation simulation method, the evolution process of rainfall induced debris flow on slope are simulated by establishing the model, parameter setting, grid division, boundary condition setting and calculation steps, obtained the deformation nephogram and deformation data of slope debris flow. Through the analysis of deformation of points, obtained the deformation law of soil elements, through the analysis of the profile and get the deformation rule of the slope soil, through the analysis of the deformation of the slope, the deformation trend of debris flow on slope under rainfall. Through analysis and comparison of the model test and numerical simulation of two kinds of circumstances, the deformation trend of slope under rainfall is roughly same.(4) To simulate the deformation process of different slope surface debris flow, different slope, deformation nephogram and deformation data of slope. Through the analysis of different slope deformation nephogram of the body, found that the greater the slope, the soil deformation is larger, and with the increase of slope deformation, the slope soil behind the rapid growth, and slower growth in front of soil deformation.