A real-time monitoring temperature-dependent risk index for predicting mine water inrush from collapse columns through a coupled thermal–hydraulic-mechanical model

Abstract

Advance forecast of water inrush can help ensure operational safety in underground engineering. In this study, a coupled thermal–hydraulic-mechanical (THM) model is developed to simulate the process of water inrush from collapse columns in coal mines with complex geological environments. Specifically, nonlinear fluid flow and heat transfer in porous media associated with the erosion and damage of collapse columns are considered. This numerical model is validated against water-inrush field data from two coal mines with regard to flow rate. Fluid pressure and temperature profiles over time are also investigated. There is a water pressure accumulation phenomenon in hidden collapse columns. Temperature is found to change more significantly than velocity in the early stages of water inrush. In addition, the spatial variation of temperature can be divided into three zones during the process of water inrush. According to the rules governing the spatio-temporal variation of temperature, a novel method utilizing a real-time monitoring temperature-dependent risk index (TRI) and a water inrush induced increasing temperature zone (WIT) is proposed to determine whether and where water inrushes will occur. This study demonstrates how this novel method can predict water inrush and overcome the main limitations in previous studies where temperature was used as a predictor. This method has the potential to be applied in practice to better understand the risks related to coal mine management and water inrush and thus improves mine safety.