Numerical Simulation on the Seepage Properties of Soil-Rock Mixture

Ning Zhao,Ning Luo,Yingchao Wang,Bo Meng

doi:10.1155/2018/1859319

Ning Zhao, Ning Luo + Show 2 more

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https://doi.org/10.1155/2018/1859319

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Abstract

To reveal the mechanism of water inrush in a fault tunnel and study the influence of different structures on the seepage process, a filling structure composed of a soil skeleton (fixed particles), a movable particles phase, and a water phase is constructed to simulate the rock mass broken by the fault. Fluent software is used to simulate the migration of the water phase in three different filling structures under different initial water velocities and dynamic viscosities. The variation law of the seepage time with the initial water velocity and dynamic viscosity in the three types of filling structures is obtained. The research shows the following: (1) the looser the filling structure, the greater the influence of gravity on the water phase seepage; the more compact the filling structure, the greater the spread range of the water phase and the more uniform the spread of the water phase. (2) The seepage time decreases with the increase in the initial water velocity. The seepage time and initial water velocity can be fitted by an exponential function. The effect of initial water velocity on seepage time is much greater than that of the structure. (3) The seepage time is related to both the dynamic viscosity and the structure. The seepage time increases with the increase in dynamic viscosity.

Highlights

In recent years, with the vigorous development of the China’s major transportation infrastructure, the depth of tunnel excavation has been continuously increasing, and the geological conditions for tunnel construction are complicated and changeable
In the process of tunnel construction, the major safety accidents caused by the water inrush disaster reached 80%, of which 30% were caused by fault water inrush [4]
E distance between the fixed particle phases of filling structure 1 is the largest, and the structure is the loosest; structure 3 is the most compact, and structure 2 is in between the other two. e figure shows that when the dynamic viscosity is the same, the seepage time required by structure 1 is in between those of structure 2 and structure 3. us, the seepage time is related to both the dynamic viscosity and the structure

Summary

Introduction

With the vigorous development of the China’s major transportation infrastructure, the depth of tunnel excavation has been continuously increasing, and the geological conditions for tunnel construction are complicated and changeable. Based on the fluid-solid coupling theory, Li et al [22, 23] studied the water inrush mechanism of coal seam floor faults and column collapse by numerical simulation and reproduced the whole process of the initiation of fractures, the activation of faults, and the formation of a groundwater inrush channel. The numerical simulation method is used to study the water migration in different structural pores of faultfractured rock mass. After the fault is exposed, the flowing water enters the pores of the fractured rock masses and causes the gradual loss of filling particles in the pores until the formation of the water inrush channel, eventually inducing a water inrush disaster. A numerical simulation is used to study the migration of water in three different structural pores of the fractured rock mass, and the seepage-flow transformation mechanism of the fillings in the pore of the fractured rock mass is revealed.

Numerical Analysis

Calculation Results and Discussion

Conclusions