Research on the Formation Mechanism of Seepage Channels in Broken Rock Mass under the effects of Particle Migration

A large number of statistics indicate that broken rock mass always transforms into a flowing channel and leads to water inrush disasters in mining engineering, such as fault, karst, and strongly weathered rock mass. During the process of water inrush, the structure of the broken rock mass is constantly changing due to seepage erosion under high-velocity flow. Therefore, it is of vital importance to quantitatively evaluate the flow behavior of the water inrush related to the seepage erosion in order to prevent or reduce the risks. This study described a coupled nonlinear flow model, which couples the high-velocity seepage, the small particle migration, and the evolution of the broken rock mass structure. The model was verified firstly for simulation of nonlinear flow behavior by comparing with the traditional one. Then, the proposed model was used to simulate the evolution of particle migration and seepage properties of the water inrush through broken rock mass by a numerical case. The simulation results generally agree well with the existing experimental results. The simulations indicate that small particle migration causes the unstable characteristics of the seepage and the heterogeneity properties of the broken rock mass, which lead to the nonlinear flow behavior of the water inrush in both time and space. From a different perspective, it also indicates that the proposed model is capable of simulating the interaction of high-velocity seepage, small particle migration, and evolution of broken rock mass structure in the process of water inrush.

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Study on formation mechanism of granite eluvium landslide by field rainfall simulation

10.21203/rs.3.rs-805661/v1 ◽

2021 ◽

Author(s):

Wenkai Feng ◽

Rui Hu ◽

Huilin Bai ◽

Yiying Wu ◽

Hongchuan Dai

Keyword(s):

Formation Mechanism ◽

Physical Simulation ◽

Water Pressure ◽

Particle Migration ◽

Local Failure ◽

Rainfall Simulation ◽

Residual Soil ◽

Slope Surface ◽

Soil Pressure ◽

Slope Structure

Abstract Granite residual soil is a kind of special soil, which is easy to induce geological disasters under the condition of heavy rainfall. Taking the mass landslides in Beiling area, Longchuan County, Guangdong Province as the background, the formation mechanism of typical landslides was explored by means of physical simulation, and the following conclusions were obtained: ① the influencing factors of landslides were rainfall intensity, physical and mechanical properties of rock and soil mass, slope structure; ② Rainfall does not cause the abnormal increase or decrease of soil pressure and pore water pressure in the slope, indicating that the failure of the slope is limited to the local failure of the slope surface and the slope toe, and there is no overall deformation and failure trend; ③ On the surface of the slope, the slope is eroded by rainfall, and on the foot of the slope, the free surface collapses and undergoes erosion. On the whole, the slope shows the characteristics of "step by step retreat and damage in turn"; ④ The evolutionary process of landslide can be divided into the following four stages: original slope evolution stage, soil particle migration stage, slope surface local failure stage and overall instability stage.

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