Study on a Coupled Thermal–Hydraulic–Mechanical Model for Water Inrush from Collapse Column

A coupled thermal–hydraulic–mechanical (THM) model for water inrush from collapse column was carried out in this paper. An erosion equation was considered to simulate the mass loss in collapse column. Then the THM coupling equations and the erosion equation were solved in COMSOL to study the porosity, permeability, velocity, water pressure, temperature, and displacement change rule with time. Results indicate that the porosity, permeability, velocity, water pressure, and temperature increase with time due to the mass loss in collapse column, which show the evolution process of water inrush from collapse column. The increase of water pressure makes the displacement decrease with time. The increase of water pressure in collapse column also makes the pressure increase in coal seam floor, which can make the floor water inrush be more likely to occur.