Study On Load Transfer Law Of Grouting Backfill Under Extremely Thick Igneous Rock

As a special overburden structure,it often leads to the occurrence of dynamic phenomena in the mining under the thick rock,which seriously affects the safe production.It is an important reason for this kind of disaster because of the concentrated stress of the coal caused by the huge rock formation.It is effective to reduce the stress concentration caused by the suspension of the rock mass by the grouting of the rock mass in the lower part of the thick rock formation by the ground drilling.In the implementation of this method,the effect of grouting filling parameters on the load transfer characteristics of overburden and the stress transfer of coal seam is the key to the engineering effect.Therefore,the paper takes the numerical simulation experiment as the main research method,and studies the feeding law of grouting under the thick igneous rock,and validates it through engineering practice.The influence of the key filling parameters such as injection-production ratio and grouting filling horizon on the dynamic stress transfer under the thick igneous rock is revealed.Due to the downward transfer of the load on the overburden load,the stress distribution of the mining stress will be changed after the grouting in the thick and large igneous rock,and the bearing capacity of the mined-out area is increased and the solid coal stress concentration is slowed down.,The process parameters that affect the load transfer are the injection-production ratio and the filling horizon.It is found that the key factor controlling the load transfer is the injection-production ratio(the filling capacity),and the effect of the filling horizon on the load transfer is much smaller.With the increase of the injection-mixing ratio,the stress peak of the goaf area is obviously increased,the peak value of the lateral stress of the coal body,the concentration coefficient of the coal body is obviously reduced,and the stress is greater than that of the coal mining area.The range of influence is reduced;when the injection-production ratio is 50%,the increment of stress concentration is up to 20%.Under the same conditions of injection and production,the higher the grouting layer,the smaller the concentration of the side of the coal,the better the effect of grouting loading.Therefore,the implementation of grouting under the thick corrosive rock,in the protection of the amount of filling under the premise,you can give priority to choose the bottom interface as a filling layer.The relationship between the support rate and the filling parameters of the goaf is obtained.The support ratio of mined-out area increases with the increase of injection-production ratio,and decreases with the increase of grouting filling level.In the mining of 150 m under the conditions of injection and production ratio of 32% to 65%,mined-out support rate of 13% to 39%;in the same injection and production ratio,with the widening of the width,support rate will be significantly increased Big.When the filling layer is 70 m ~ 170 m above the coal seam,the supporting rate of the goaf is 46% ~ 39%.In the same grouting filling layer,the support rate decreases with the increase of the mining width.At the same time,it is concluded that the supporting area of goaf is negatively correlated with the characteristic parameters of coal mining stress,that is,when the range of supporting zone is increasing,the stress concentration concentration,The range of dynamic stress is decreasing.Experiments on grouting filling for disaster reduction under extremely thick igneous rock at the Coal Face ?1026 of Haizi Coal Mine.Effectively reducing the dynamic stress caused by the concentration of mining disasters,did not appear due to the huge igneous rock caused by mining disasters,safe production of raw materials 563,000 tons,to achieve the purpose of safe recovery.