Application Study On Underground Pressure Online Monitoring System Based On Optical Fiber Sensing In No.5 Mine Of Yangmei Group

In order to ensure the safety of coal mine production,real-time monitoring of underground pressure is an essential technical means.However,as far as the current development is concerned,most of the underground pressure monitoring equipment adopts mechanical or electrical energy for signal transmission,so it is not intrinsically safe.Under this background,firstly,by analyzing the basic principle and characteristics of optical fiber sensing,as well as the related requirements of underground pressure monitoring,the online monitoring system of optical fiber sensing mine pressure has been constructed.Secondly,the concrete monitoring scheme has been designed and implemented in the return air roadway of 8402 working face,and analyzing representative monitoring data.Its main contents are as follows:(1)The basic theory and characteristics of optical fiber sensing technology are studied,and the demand of mine pressure monitoring in 8402 return air roadway is analyzed,and the basic optical fiber sensing equipment is determined.Through the establishment of the software system and hardware system of the monitoring system,the structure of the optical fiber sensing pressure monitoring system with real-time,early warning and other functions has been constructed.(2)Based on the principle of economy,rationality and comprehensiveness,by analyzing the relevant theory of supporting pressure,the influence range of leading abutment pressure in 8402 working face is 45.5 m,the range of elastic zone is 32.6m,and the range of limit equilibrium zone is 12.9m.Preliminary determination of the need to deploy 5 stations;Then flac3 d is used to carry out numerical simulation to optimize the location and number of stations and to determine the sensors and layout positions required for each measuring point.(3)The monitoring scheme designed above is reasonably implemented and arranged in the 8402 return air roadway,and the underground pressure data of the roadway is real-time sensed.The analysis of perceptual data shows:(1)the influence range of leading bearing pressure of 8402 face is between 70 m and 75 m,and its peak stress is between 16 m and 20 m during the mining period.(2)During the period from July 26 to September 26,the range of shallow and deep delamination is 0~2.5mm and0.5mm,which is in the range of safety value.In the working face mining period,it can be divided into three stages,namely,slow delamination stage,delaminationincrease stage and rapidly increasing stage.With the advancement of the working face,the load of bolt(cable)increases as a whole.The axial stress of surrounding rock in the middle part of the anchor rod is the largest,the tail is the second,and the end is the least.