Design Of Real-time Monitoring Instrument For Deformation Of Pressure Relief Groove In Coal Mine Shaft

The pressure relief groove of the wellbore can effectively absorb the vertical pressure of the wellbore,but the long-term effects of geological activities such as underground flowing water and quicksand will cause deformation of the pressure relief groove,which will bring hidden dangers to coal mine safety production.If the measures such as grouting reinforcement around the wellbore are not taken in time when there is a small change,it will cause greater deformation of the wellbore,which is difficult to repair and affects the safety production of coal mines.If the deformation of the pressure relief groove can be monitored in real-time,the deformation and change trend can be known,and the countermeasures can be taken immediately when the controllable deformation occurs,the maintenance difficulty and maintenance cost can be reduced,which is of great significance to ensure the safety production in coal mines.In this thesis,an automatic and real-time monitor for the deformation of the pressure relief groove is designed.The monitor is composed of several underground extensions and an above-ground host.The host and the extensions are connected by 485 bus.Each extension sets its own address through the address coding circuit,and the host communicates with each extension uses by cyclic scanning according to the address information,so as to achieve the purpose of monitoring multiple pressure relief grooves at the same time.LVDT displacement sensor with high precision and good stability is used by the extensions to detect the tiny deformation of the pressure relief groove of the wellbore and upload the deformation information of the pressure relief groove to the ground monitoring host.If the deformation of the pressure relief groove exceeds the preset threshold,the host computer will automatically start the acousto-optic alarm device through the optocoupler isolator.The deformation data of the pressure relief groove at different time points by the host computer dynamically will be displayed in the form of curves through the LCD screen,and the daily and weekly deformation of the pressure relief groove will be analyzed,which the deformation trend of the pressure relief groove can be grasped by macroscopically and will be served as an effective basis for the next protection measures.After stand-alone and on-line testing in the laboratory,the monitor has accurate and stable data,strong real-time performance,and all functional indexes meet the design requirements,so it can be installed and tried in the well.