Research On Deformation And Control Of Overlying Strata In Coordinated Filling Mining Of Short-walled Extra-thick Coal Seam Under Main Aquifer

With its inherent characteristics,coal resources occupy a dominant position in Chineses energy structure.This situation is difficult to change in the short term.With the shift of Chinese coal mining focus,Shanxi,Shaanxi and Mongolia in the northwest have become the main producing areas of coal resources.Chinese coal resources and water resources are in reverse distribution.Water resources are extremely important for the coal-rich Shanxi,Shaanxi,and Inner Mongolia regions.Underground aquifers are an important water source in this area.Most mines often have working faces during the mining of coal resources.Problems such as serious water gushing and destruction of water resources.How to realize the safe mining of coal resources and the protection of water resources is one of the core problems to be solved urgently in this area.In order to realize the safe mining of coal resources and do a good job of protecting water resources at the same time,find the key to the deformation control of the overlying rock suitable for the mining of the extra-thick coal seam under the strong water-rich rock layer.This paper analyzes the influencing factors of overburden deformation and concludes that short-wall working face and backfill mining technology have a good control effect on overburden deformation.Therefore,the overburden deformation and control of ultra-thick coal seam under main water-bearing layer and short-wall coordinated filling mining are proposed.Content of the study.Based on the theoretical analysis,numerical simulation,engineering design and other research methods used in this article,corresponding mechanical models have been established for different conditions such as single working face mining and whole area mining,and different working face sizes and different backfilled ratio have been carried out for short-wall coordinated filling mining.The deformation characteristics of the overlying rock under the effect of the rate and its synergy are simulated,and the corresponding engineering design is carried out according to the geological conditions of the specific mining area.The main research results obtained are as follows:(1)Aiming at the dual requirements of coal resource mining and water resource protection in Northwest China,the Gaojiapu Coal Mine is taken as an example to analyze a series of problems in its mining process,and the short-wall coordinated filling mining technology is proposed for the reason of large water inflow.Analyzed its technical principles and advantageous characteristics of controlling overlying rock deformation,and concluded that factors such as mining height,working face length,and backfilled ratio are the key to controlling overlying rock deformation with the shortwall coordinated filling mining technology;(2)The elastic thin plate mechanics model was established for the stoping of a single working face,and the roof stress characteristics under the synergistic effect of the working face size and the backfilled ratio were obtained;the roof and the overlying rock deformation formed by the mining unit of the working face were constructed for the working face jump mining The mechanical structure model determines the separation distance between the working faces;establishes the weak rock fixed beam model for the whole area mining,and determines the peak point of the overburden crack development.Taking Gaojiapu Coal Mine as an example,the control requirements for key parameters of coal resource mining under the conditions of this mine are obtained;(3)Aiming at the key to overburden deformation control such as mining height and working face length,numerical software was used to simulate the deformation characteristics of the overburden rock by changing the backfilled ratio and the length of the working face,and it was concluded that the working face length of the same mining height is different,and the working face length is different.Under the conditions of the same mining height and the reasonable distance between working faces in different mining stages,the stress state,displacement,and plastic zone development of the overlying rock are carried out according to the deformation characteristics of the overlying rock during the entire mining cycle of the short-wall coordinated filling mining technology.Based on the simulation,the design process of key parameters for short-wall coordinated filling mining to control overlying rock deformation was obtained.The paper has 51 pictures,6 tables,and 107 references.