Study On Abandoned Roadway Filling Material And Filling Technology Of 3122 Fully Mechanized Top-coal Caving Face In Jingxin Coal Mine

The deformation and failure of surrounding rock is serious because of abandoned roadway disrepair,especially the roadway which is perpendicular to the working face,abandoned roadway will have the phenomenon of roof fracture and two sides instability because that surrounding rock is unbearable to the abutment pressure during mining.Working face will be long span and long time when through the abandoned roadway,which is not security and stability to working face.Filling technology can effectively control the deformation of abandoned roadway surrounding rock,and the research of filling materials is also a major problem in the recent years.This paper was based on the 3122 fully mechanized top-coal caving face in Jingxin coal mine,studied abandoned roadway filling material and technology.The main research contents and results are as follows:(1)The structure characteristics and deformation mechanism of the surrounding rock were analyzed.The failure form of abandoned roadway was"shear-tensile crack"composite failure,which mainly showed as roof sinking,bottom bulge and two outbursts.Abandoned roadway destroyed the integrity of coal seam and aggravated the advanced fracture of roof overburden structure.(2)A new kind of inorganic cementitious filling material was proposed by experiment.It was mainly composed of cement,lime powder,foam stabilizer and foaming agent,according to 1:1.5 water cement ratio of mixed stirring,a certain filling properties of the gel would be formed after foaming 2~3 times,and the material strength could reach 0.7~0.9 MPa.(3)The deformation of abandoned roadway surrounding rock of 3122 fully mechanized caving face was controlled by grouting filling technology in Jingxin Coal Mine.This paper proposed the filling technical solutions and processes,the filling system and equipment were determined,and the preliminary budget for the filling materials was made.(4)FLAC~3DD numerical simulation was used to analyze the stress distribution and deformation law of surrounding rock in the abandoned roadway.Compared with the prior to filling,the vertical stress and the displacement of the surrounding rock were reduced after filling,and the damage range of the plastic zone was reduced,the surrounding rock of the transport trough was basically safe and stable.(5)The research results were applied in the 3122 fully mechanized top-coal caving face in Jing-xin coal mine.The results showed that using inorganic cementitious material to fill the abandoned roadway can effectively control the deformation and failure of the surrounding rock,and ensure the safety of working face through the abandoned roadway.Meanwhile,the filling technology brought economic benefits to the mine as much as more than 20 million yuan.