###### Abstract  
A coupled thermal-hydraulic-chemical (THC) model was carried out in this paper to study the influence of rock heterogeneity and the coupling effect of temperature, groundwater, and hydrochemistry on rock damage. Firstly, the hydrochemical and hydraulic erosion equations were established. The equations of the coupled THC model were established by combining the hydrochemical and hydraulic erosion equations, the flow equations, and the heat transfer equations. Weibull distribution was adopted to govern the heterogeneity of initial rock porosity distribution. Secondly, the influence of the hydrochemistry, the temperature and the initial porosity heterogeneity on porosity and fluid velocity change was studied. Then the rock damage rule changed with time at different pH values and temperature was studied. Finally, an actual deep coal mine model was established to apply the THC model to predict water inrush. Results indicate that: (1) The average porosity and average fluid velocity approximately show linear growth and exponential growth with time, respectively, and their growth rates increase with decreasing pH value and increasing temperature in a certain acidity and temperature range. (2) The increase of initial porosity heterogeneity has little influence on porosity change, but it can increase the fluid velocity growth rate. The porosity heterogeneity and fluid velocity heterogeneity approximately show exponential growth with increasing time, and the rock heterogeneity growth contributes to form cracks. The increase of temperature and decrease of pH value have little influence on the porosity heterogeneity, but they can increase the growth rate of the fluid velocity heterogeneity. (3) The rock damage shows linear growth with time, and its growth rate increases with decreasing pH value and increasing temperature in a certain acidity range and temperature range. (4) The increase of rock heterogeneity can increase the possibility of water inrush. coupled thermal-hydraulic-chemical model; rock damage; chemical erosion; Weibull distribution; rock heterogeneity; water inrush 2019 9 2195 229 2019 229 2019 229 2019 229 2019 229 2019 229 2019 229 2019 229 2019 229 2019 229 2019 229 2019 229 2019 229 2019 229 2019 229 2019 229 2029 2019 229 2  
water intrusion is an important measure to guarantee mine workers' security. Water inrush is more likely to occur under the interaction of high ground temperature, high ground water pressure, high ground stress, and a complex hydrochemical environment in deep mines. The impact of a single factor of high temperature [1], water pressure [2], or hydrochemistry [3] has great influence on rock properties, and their coupled processes will have a greater and more complex influence on rock properties. Therefore, it is necessary to study the coupled thermal-hydraulic-chemical (THC) effect on rock damage to predict water inrush. The framework of international projects like DEvelopment of COupled models and their VALidation against EXperiment (DECOVALEX) have dramatically promoted the study of the thermal-hydraulic-mechanical (THM) coupling process [4; 5]. Based on the mass, energy and momentum conservation, and number of experiments, these researches have made great progress in the combined effect of fluid flow and heat transfer on rock or soil properties [6; 7; 8; 9]. For instance, [PERSON] et al. [8] developed a THM coupling model to simulate the combined effect of fracture fluid flow and heat transfer on matrix stability and shearing dilation behaviors. Based on these models and experiments, the rock damage rule was applied to deep mining and predicting water inrush [10; 11]. In recent years, considering the hydrochemical erosion, the research on coupled hydraulic-mechanical (HC) [12], THC [13], mechanical-hydraulic-mechanical (MHC) [14; 15] and thermal-hydraulic-mechanical-chemical (THMC) [16; 17; 18; 19] effect on rock damage has made great progress. For instance, [PERSON] et al.