Study On The Spatial-temporal Evolution Law Of Ground Pressure In Gangue Solid Compacted Backfilling

Solid gangue filling technology is an important green mining technology,which mainly uses gangue as aggregate and mixed with other auxiliary materials to fill the goaf,controls the appearance of ground pressure and overlying strata movement degree,and realizes the purpose of safe and green coal replacement.However,in the practice of gangue filling engineering,there are some problems such as low compactness of backfill and poor control effect caused by insufficient understanding of the spatiotemporal mechanism of ground pressure,which restrict the long-term and extensive application of solid gangue filling mining technology.Therefore,in order to further understand the coupling effect of filling body and overlying strata and the spatiotemporal characteristics of strata behaviors,and improve the compactness and filling rate of gangue solid,based on the background of compacted backfilling of gangue solid,this paper uses the methods of theoretical analysis,numerical simulation,similar material experiment and laboratory experiment to systematically study the spatial-temporal evolution law of compacted filling strata behaviors and overlying strata movement.The main results are as follows:(1)Based on the analysis of the structure and deformation characteristics of overlying strata,the relationship between the deformation curvature and the filling ratio of the continuous curved beam is derived,The spatiotemporal coupling model of compacted backfilling and overlying strata is established,and the spatiotemporal evolution model of compacted backfilling is analyzed,finally,the spatiotemporal quantitative relationship between the settlement deflection of the compacted filling roof and the strength of the filling body is determined.(2)The self-designed simulation experiment-bench was used to study the lateral compaction characteristics of the gangue.The best gradation of the compacted filling gangue was obtained by the compaction experiment,which was the Talbol coefficient n= 0.4 grain size gradation.The mechanical aging characteristics of the gangue solid were studied by using the aggregate mixed with fly ash,cement and other auxiliary materials.(3)Based on the similar material model of compacted filling,the movement and deformation of overlying strata,the change law of the strata behaviors and the force on the filling body are studied.It is found that the strata behaviors and the movement lawof overlying strata show certain spatiotemporal characteristics.(4)Based on the study of mechanical properties of filling materials,the spatial-temporal variation of stress and displacement of overlying strata under different filling rate and strength of filling body is analyzed by using numerical simulation software.(5)Based on the case study of Xingtai gangue solid compacted filling project,the monitoring results of bracket support resistance,separation of roadway roof and ground settlement in the process of filling mining are analyzed,and the temporal and spatial characteristics of strata behaviors and overlying strata movement law of compacted filling are studied,and the research conclusion is finally verified.