Research On Surrounding Rock Control Technology Of Roadway Retaining Along Goaf For Pressure Relief In Sihe No.2 Mine

With the large-scale mining of coal resources,the resources are becoming increasingly scarce,and the traditional mining methods and techniques of retaining coal pillars urgently need to be optimized.The roof-cutting and pressure-relief mining technology without coal pillars along the goaf is the application of comprehensive technologies such as roadway surrounding rock support,energy-accumulating pre-splitting joint blasting,temporary support in dynamic pressure areas,and gangue support beside roadway.Keeping roadways along the goaf can realize the mining area without sectioned coal pillars and no additional filling bodies.This technology greatly improves the recovery rate of coal resources and reduces the amount of roadway excavation works.It has broad application prospects and high research value.This thesis takes Sihe No.2 well 97307 working face 97214 as the research background,using various methods such as laboratory test,theoretical analysis,numerical simulation and field test to study the pressure relief edge of Sihe No.2 well 97307 working face.The main achievements of the surrounding rock control technology of empty roadway are as follows:(1)Based on the collection and sorting of the engineering geological conditions of the97307 working face,the methods of on-site drilling and coring,roof peeking,and laboratory tests were used to master the lithological distribution of the roof and floor of the 9# coal seam and the mechanical properties of coal and rock mass..(2)Based on the movement law of the overlying strata of the stope,the characteristics of the roof movement are analyzed.The roof structure is divided into "load-bearing structure" and "pressure relief structure".The subsidence of the key block B mined-out area and the roadway mined-out area are analyzed.The side subsidence is calculated,and the movement characteristics of the key block B can be seen.By appropriately increasing the roof cutting height,the roof within the cutting seam range can collapse in time to fill the mined-out area,which can inhibit the rotational subsidence of the broken rock block and improve the stability of the roadway Sex.(3)The surrounding rock movement characteristics of roadway retaining have obvious stages.The surrounding rock movement of retaining roadway can be summarized as the advanced influence stage of primary mining,the dynamic pressure influence stage of retaining roadway,the stabilization stage of retaining roadway,and the advanced influence stage of secondary mining.According to the different roof rock structures in the first three stages,the research on roof deformation and control is carried out to provide a basis for the subsequent design of roof cutting pressure relief parameters.(4)Based on the research on the principle,technological process and key technology of the technology principle,technological process and key technology of cutting roof,pressure relief and remaining roadway along the goaf,theoretical analysis and numerical simulation are used to conclude that the roof pre-cracking slit height is 8m and the angle is 10° as the optimal cutting Roof parameters: Combining with the geology and mining technical conditions of the 97,307 working face,the 97214 roadway,the design optimization of the roadway retaining reinforcement support,temporary support,gangue retaining support and blasting key parameters are carried out in sequence.(5)The on-site observation results of the 97214 roadway retention stage show that:within 60 m of the lagging working face,the roadway pressure appears the most intense;the lagging working face is 60m?150m,and the roadway pressure appears more relaxed;after the lagging working face is 150 m,the roadway deformation tends to be stable.The results of mine pressure monitoring at the secondary reuse stage of Lane 97214 show that: in the secondary mining stage,the surrounding rock deformation of the roadway is generally greater than the dynamic pressure impact stage of the roadway;the secondary mining's leading influence range is about 40 m,of which the leading influence is within 15 m.The deformation of the roadway is the most severe;the leading influence range and extent of the secondary mining is obviously greater than the leading stage of the primary mining.(6)The technology of cutting the roof to relieve pressure and staying along the goaf has been adopted to realize the pillar-free mining at the 97307 working face.As of March 2020,the 97307 working face has been successfully mined,the length of the roadway retained has reached 1300 m,83,900 tons of more coal resources have been recovered,and the income of33,567,300 yuan has been increased.During the reuse period,the roadway meets the requirements of normal use.The research results of this thesis solved the problem of the shortage of mining replacement in the No.2 shaft of Sihe Coal Mine,and realized the pillar-free mining in the 97 panel.At present,the industrial test and promotion have been carried out in 2 mining faces in the 97 panel,and the accumulated coal resources have been recovered.Up to 167,800 tons,the full use of resources has been realized and considerable benefits have been brought to the mine.