A Coupled Thermal-Hydraulic-Mechanical Nonlinear Model for Fault Water Inrush

Weitao Liu,Jiyuan Zhao,Yuben Liu,Yanhui Du,Ruiai Nie

doi:10.3390/pr6080120

Abstract

A coupled thermal-nonlinear hydraulic-mechanical (THM) model for fault water inrush was carried out in this paper to study the water-rock-temperature interactions and predict the fault water inrush. First, the governing equations of the coupled THM model were established by coupling the particle transport equation, nonlinear flow equation, mechanical equation, and the heat transfer equation. Second, by setting different boundary conditions, the mechanical model, nonlinear hydraulic-mechanical (HM) coupling model, and the thermal-nonlinear hydraulic-mechanical (THM) coupling model were established, respectively. Finally, a numerical simulation of these models was established by using COMSOL Multiphysics. Results indicate that the nonlinear water flow equation could describe the nonlinear water flow process in the fractured zone of the fault. The mining stress and the water velocity had a great influence on the temperature of the fault zone. The temperature change of the fault zone can reflect the change of the seepage field in the fault and confined aquifer. This coupled THM model can provide a numerical simulation method to describe the coupled process of complex geological systems, which can be used to predict the fault water inrush induced by coal mining activities.

Highlights

Fault water inrush frequently occurs in China’s coal mines, which is a major threat to mine safety and production
When the water pressure was 4 MPa and 10 MPa, the water velocity had a rapid increase at the junction of the confined aquifer, fault, and coal seam, which indicated nonlinear flow processes
When the water pressure was 4 MPa and 10 MPa, the water velocity had a rapid increase at the junction of the confined aquifer, fault, and coal seam, which indicated nonlinear flow processes in

Summary

Introduction

Fault water inrush frequently occurs in China’s coal mines, which is a major threat to mine safety and production. The complexity of geological systems in deep mines, including high ground temperature, high ground water pressure, and high ground stress, has motivated researchers to consider the temperature (T), hydraulic flow (H), and mechanical deformation (M) coupling model for fault water inrush. Tsang et al [6] summarized some studies of the project DECOVALEX III. These studies included two field experiments on coupled THM processes in a crystalline rock-bentonite system and in unsaturated tuff, three benchmark tests to evaluate the impact of coupled THM processes under different scenarios and geometries, and different approaches and computer codes for coupled THM processes. Anju coal coal mine mine of of China.

Methods

Results

Conclusion