Thermal Effect Of Filling Body And Stope Thermal Environment Analysis In Maoping Lead-zinc Mine

With the shift of mine mining to the deep,high temperature heat damage has become one of the important factors restricting the safe mining.In addition,with the continuous popularization of filling mining method,heat production by hydration of filling body further aggravates the underground heat damage.Therefore,it is of great importance to study the law of hydration heat production of filling body and the change law of stope wind temperature when it exists for improving the underground thermal environment.Aiming at the thermal damage stope of Maoping lead-zinc mine,this thesis studies the law of hydration heat production of backfill body and the influencing factors of heat damage in low-ground temperature mine by combining theoretical analysis,laboratory experiment,field test and numerical simulation,providing certain theoretical basis for controlling hydration heat production of backfill body and improving underground thermal environment.(1)In this thesis,based on the tailing sand and mechanism sand collected in the field,sixteen kinds of filler specimens with different water-cement ratios and different aggregate ratios were prepared for the filler hydration exothermic experiments to analyze the change law of hydration heat and heat production of filler materials with time.The results show that: the experimental filling bodies will rapidly warm up to the peak temperature of about 28℃ within 24 hours,after which the temperature will rapidly decrease within 48 hours and finally slowly drop to the ambient temperature;among the three factors of slurry concentration,ash-sand ratio and the proportion of mechanism sand in the aggregate,the size of the influence on the heat production of the filling body is in the order of: slurry concentration,ash-sand ratio and the proportion of mechanism sand in the aggregate;the slurry concentration has the smallest influence on the heat production of the filling body on the first day The effect of slurry concentration on the heat production of the filler is the smallest,but still the highest of the three;the effect of ash-sand ratio on the heat production of the filler increases day by day;the proportion of the mechanism sand in the aggregate significantly affects the first day(2)Based on the field measurement data,the temperature gradient and thermal environment parameters of the mining site were obtained.A physical model of the mining site was established,and numerical simulations were conducted to study the effects of four heat sources,including wind flow temperature,human heat source,electromechanical equipment and filling body,on the temperature of the mining site and surrounding rocks under the lower ground temperature,and the numerical calculation results were verified by the measured data.The results show that: the ground temperature at the current mining level of Maoping Pb-Zn mine is low,21.60℃,and the ground temperature gradient is 1.66℃/hundred meters;the heat generated by the filling body will not only be directly transferred to the mining site by the wind flow,but also conducted to the wall of the tunnel through the surrounding rock,causing the temperature of the mining site to increase;for every 1℃ increase in ground temperature,the C temperature of the mining site section increases by 0.082℃;the influence of each heat source on the thermal environment of the mining site in Maoping Pb-Zn mine The primary and secondary relationship of the degree of influence of each heat source on the thermal environment of the mining site in Maoping Pb-Zn mine is: wind flow temperature(46.33%)> filling body(25.35%)≈ electromechanical equipment(23.55%)> human heat source(4.77%).(3)Combining with the actual situation of the site,the ground temperature,thermal conductivity of the surrounding rock,inlet air temperature and inlet air speed are changed,and the numerical simulation of the quarry under the conditions of different influencing factors is carried out to study the influence of different influencing factors on the humidity and temperature of the quarry.The results show that: when the initial humidity of the quarry is 0.97,the humidity of the inlet wind flow and the wind speed are 0.5 and 10m/s,the humidity of the front end of the quarry will be reduced to 0.6～0.7,and the more obvious influence on the humidity of the quarry is the humidity of the inlet wind flow,and the effect of increasing the wind speed is very limited to improve the humidity reduction of the quarry;with the increase of the distance between the section and the wall of the filling body,the influence of the inlet wind speed,thermal conductivity and ground temperature on the quarry With the increase of the distance between the section and the wall of the filling body,the influence of the inlet wind speed,thermal conductivity and ground temperature on the temperature of the quarry gradually increases,and the influence of the inlet wind temperature on the quarry first decreases and then increases;the influence of the four factors on the temperature of the quarry wind flow is as follows: inlet wind temperature,ground temperature,inlet wind speed and thermal conductivity.