Study On Size Optimization Of Section Small Coal Pillar In Sangou Xindu Coal Industry

Because of the current situation,such as difficulty in determining the size of coal pillars,surrounding rock deformation is serious,and coal resources waste,taking the Sangou Xindu coal industry as the engineering background,this paper examined the roof cutting and pressure relief technology of small coal pillar gob-side entry driving by means of theoretical analysis,laboratory experiments,numerical simulation and field application.This paper analyzes the stress distribution and deformation of surrounding rock of coal pillar,and determine the reasonable width of coal pillar.Firstly,the relevant geological conditions of the mine were understood through field investigation and the coal and rock mass were sampled on site.The physical parameters such as tensile strength,compressive strength,and shear strength of the coal samples were obtained through laboratory tests.Secondly,according to the theoretical analysis of roof cutting and pressure relief,it is concluded that reasonable roof cutting parameters are the key to the success of goaf excavation.The distribution characteristics of side stress in goaf under different roof cutting parameters are analyzed by numerical simulation.The results show that when the cutting Angle is 130° and the cutting height is 12 m,the pressure relief effect is better.At this time,the width of the lateral stress reduction zone in the goaf is 12 m.If the coal pillar and roadway are arranged here,the width of small coal pillar should not be greater than 7.8m.Therefore,four schemes with small coal pillar sizess of 4m,5m,6m and 7m are designed.Through numerical simulation analysis of stope stress evolution law and roadway surrounding rock deformation characteristics,5m is determined to be the most reasonable width of coal pillar under the state of cutting roof.According to the above research,the hydraulic fracturing roof cutting scheme is implemented for the 1301 return air roadway,a 5m wide section of coal pillar is set between the 1203 transport roadway and 1203 working face,and the support scheme is designed for the transport roadway of 1203 working face.Through the monitoring of the displacement of roadway surrounding rock and the stress of anchor bolt(cable),the deformation of mining roadway and the stress of small coal pillar can be mastered in time.The monitoring results show that the deformation and stress monitoring data of the roadway surrounding rock are in a controllable range,and the roadway has good usability.The paper has 51 figures,13 tables,and 73 references.