| As an important part of our country’s existing energy,coal plays a huge role in industrial development,production and life.At this stage,the total amount of coal resources stored in shallow parts of our country that can be mined is decreasing,and the trend of mining deep coal resources is inevitable.When the mine is mining deep,it will encounter complex geological problems such as high ground temperature,high ground stress and high concentration of gas,which not only increases the difficulty of mining,but also threatens the safety of mine mining.Heat damage is the most serious problem.Existing mine heat damage control technologies are mainly achieved by isolating high temperature heat sources,optimizing ventilation,and introducing cold media.Although the underground temperature can be reduced to a certain extent,the frequency of heat damage accidents can be reduced,but these methods have high input cost,and the temperature of the surrounding rock cannot be effectively reduced from the root.Therefore,in order to reduce various accidents caused by high temperature in mines and enable coal mines to mine safely,it is necessary to take measures to reduce the temperature of the main heat source of mine heat damage—the roadway surrounding rock,reduce its heat dissipation,and reduce the temperature of the underground working environment.Based on the theory of heat transfer,the paper puts forward the method of inserting cold water pipes into the surrounding rock of the roadway,and reducing the temperature of the surrounding rock of the roadway by the method of intercepting high temperature by the cold water.In order to study the effectiveness and rationality of the method,a high-temperature surrounding rock cold water interception and cooling experimental system was built according to the similar principle,and the experiments and results were analyzed by changing the water flow rate,the passage time and the surrounding rock temperature.Through COMSOL numerical simulation software,build the cold water interception and cooling model of high-temperature surrounding rock under the experimental size,simulate and analyze the influence of cold water flow rate,temperature,inlet time and surrounding rock temperature on the cooling effect,and compare with the experimental results.It is concluded that when other conditions remain unchanged,when the cold water temperature is 5℃,the cold water flow rate is0.5m/s and the inlet time is 72 h,the surrounding rock temperature decreases the most and the cooling effect is the best.Using the parameters related to the best cooling effect of the surrounding rock obtained from the experimental and simulation results,combined with the actual situation of the mine,the cold water flow rate is 0.5m/s,the cold water temperature is5℃,and the passage time is 4800 h,and the cold water interception and cooling in the surrounding rock of the roadway is constructed.The model analyzes the influence of different diameters and different spacing layouts of water pipes on the cooling effect of water retention in the surrounding rock of the roadway in the actual mine roadway: the larger the pipe diameter of the water pipe,the more uniform the distribution in the vertical direction on both sides of the roadway,the better cooling effect.Combined with the actual situation of the mine,the optimal arrangement is when the diameter of the cold water pipe is 10 cm,and the vertical distance between the two sides of the roadway is 2.5m,it is concluded that when the length of the roadway is up to 10 km,the cooling effect of the optimal arrangement can still meet the cooling requirements,and the average temperature of the surrounding rock wall of the roadway is 25.854℃,which is still lower than 26℃,which is in line with the roadway temperature in the safety regulations.Requirements,this cooling method is feasible in engineering practice.39 figures,12 tables,and 91 references. |
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