Study On Layout And Support Design Of Track Lane Under Working Face In Extremely Close Distance Of Coal Seam Goaf In South Nine Mining Area Of Duerping Mine

In my country's primary energy composition structure,the proportion of coal has remained at around 50%.Although the proportion has declined slightly in recent years,the total demand is still rising steadily and has always been in a dominant position.Due to the difference in coal formation conditions,the occurrence status of coal seams shows a significant difference.In the joint mining of coal seams,the interaction between the upper and lower layers is constantly emerging,especially when the interval between layers is particularly small.The complete structure has been severely damaged,coupled with the collapsed coal and rock bodies,and the protective coal pillars left after the upper mining is completed form a certain stress concentration effect on the coal floor,resulting in complex changes in the stress distribution of the lower coal and rock bodies Compared with a single coal seam,it presents more complicated mine pressure phenomena and supporting technical difficulties.This thesis takes the 73903 working face of South Nine Mining Area of Duerping Coal Mine of Xishan Coal and Electric Power Company as the main research object to carry out comprehensive analysis and research,combining theoretical analysis,underground in-situ actual measurement,numerical simulation and on-site measurement to combine various research methods for mining Roadway layout and support design,the layout of the working face roadway under the very close distance coal seam goaf and the design of support parameters are proposed.The main results of the research are as follows:(1)Analyze the geological conditions of roadway in 73903 working face and carry out geomechanical testing to obtain the basic structure of surrounding rock of the roadway,the in-situ strength of surrounding rock and the distribution of in-situ stress.(2)Obtain the distribution characteristics of the plastic failure of the surrounding rock in the upper coal seam mining and the distribution law of the vertical stress field of the coal pillar.The maximum failure depth of the surrounding rock is 9m and the influence range is 25 m,forming a "inverted saddle"-like distribution state.A vertical stress reduction area appears on the side,and a significant stress concentration effect occurs at the position of the coal pillar.(3)Obtain the evolution characteristics and peak distribution law of verticalstress distribution at different depths of the bottom floor rock layer after the upper coal seam mining.With the increase of the burial depth,the vertical stress concentration gradually decreases,and the peak value gradually decreases.The stress distribution changes from the "saddle" shape The transition to a "single peak" shape eventually tends to the original rock stress.(4)Obtain the deformation characteristics and vertical stress distribution law of track roadway rock under the conditions of different layout methods and internal stagger distances.Comprehensive comparative analysis determines that the layout of the roadway staggered 13 m is the most advantageous.(5)The optimization plan of the supporting structure is proposed,and the technical parameters of the high-strength pre-tension bolt support for the track roadway in the 73903 working face,including the roof and two-gang parameter design,are implemented to realize the strong support of the roadway at one time,which is applied to the test section of the track roadway.The rock pressure observation results show that the deformation of the surrounding rock of the roadway is within the controllable range,which indicates that the choice of the layout position of the roadway and the support design are more reasonable to meet the current production needs.This thesis has 38 drawings,8 tables and 63 references.