Numerical Simulation Study On Seepage-heat Transfer Coupling Of Surrounding Rock In Mine Roadway

With the increase of mining depth,the heat damage caused by high temperature is becoming more and more serious,and the main reason of the heat damage is the heat release of surrounding rock,so it is very important to study the heat transfer of surrounding rock.In this paper,taking the surrounding rock of mine roadway as the engineering background,the mathematical models of seepage and heat transfer in surrounding rock of mine roadway with porous,single and regular fractures are established by applying the theory of heat transfer and seepage.The seepage heat transfer interaction in each surrounding rock is analyzed by finite element simulation,and the distribution law of surrounding rock temperature field is obtained.The influence of factors such as ventilation time,porosity,permeability,ventilation temperature,thermal conductivity of surrounding rock,crack opening and seepage velocity of fissure water on the distribution of temperature field of roadway surrounding rock is analyzed and studied.The main findings are as follows:(1)In the porous wet surrounding rock seepage heat transfer model,the groundwater seepage makes the temperature field distribution of the porous and humid roadway become uneven,the longer the ventilation time,the bigger the permeability,the more obvious the heat transfer;When the equivalent porosity of the surrounding rock is large,the greater the porosity is,the more conducive to heat transfer,when the equivalent porosity is small,the smaller porosity is,the more favorable for heat transfer;The influence of ventilation temperature of surrounding rock and temperate mine on the radius of heat regulating ring is not significant.(2)In the single fissure seepage surrounding rock,the contours of surrounding rock temperature field will deflect to the direction of fissure flow.The longer the ventilation time of mine roadway,the bigger the radius of surrounding rock heat regulating circle and seepage velocity,the larger the cooling area of temperature field formed by surrounding rock ventilation and fissure seepage;The faster the seepage velocity of fissure water,thesmaller the temperature increase rate of fissured water,the faster the temperature of surrounding rock decreases;The larger the crack opening degree is,the larger the area of cooling zone formed by seepage of fissure water and ventilation temperature of roadway is,the lower the temperature of fissured water is;The greater the thermal conductivity of surrounding rock body is,the higher the temperature of fissured water is,the rising gradient of temperature increases and the temperature of rock mass near fracture decreases.(3)In the regular multi-fissure seepage surrounding rock,The increase of the seepage velocity of vertical fissure,the vertical crack opening,the seepage velocity of the horizontal fissure and the opening degree of the horizontal fissure will all increase the area of the cooling zone in the surrounding rock;When the seepage water in the fissure is not flowing,the change of opening degree has little influence on the temperature field of the surrounding rock;The effect of vertical fracture seepage velocity on the temperature of horizontal fracture seepage water is greater than that of it's opening degree on horizontal fracture seepage water temperature.(4)The temperature field simulation results and experimental results of porous wet surrounding rock and single fissure seepage surrounding rock are compared and analyzed.The results show that the simulation results are in good agreement with the experimental results.The slight deviation between the experimental results and the simulation results in the porous and humid surrounding rock is caused by some uncontrollable boundary conditions in the experiment,this is considering the range of deviations,therefore,it is proved that the simulation method is feasible and the experiment is verified.