Exploration Method And Application Of Water Pressure In The Collapse Column Of Water Diversion In Renlou Coal Mine

Three collapse pillars have been discovered in Renlou Coal Mine,which are7222 collapse pillars,7218 collapse pillars,and II51 collapse pillars.This coal mine belongs to an area where there is a threat of water inrush from collapse pillars.Advance exploration must be conducted during the excavation of new horizontal roadways in the new mining area of the mine.In order to better conduct exploration work,it is necessary to conduct a comprehensive and in-depth study of the collapse column and advanced exploration technology.This article takes Renlou Coal Mine as the research object,through collecting,sorting out,and analyzing relevant data,using on-site water injection tests and numerical simulation methods,to study the development pattern of collapse columns and the surrounding pressure relief disturbance phenomenon,and has achieved a series of research results.(1)Study on the Development Morphology of Subsidence ColumnsBy collecting data on collapse columns in Renlou and surrounding coal mines,statistical analysis was conducted on the morphology and major and minor axis diameters of the development of collapse columns.Through numerical simulation,it was found that under the geological conditions of Renlou coal mine,the minimum development size of collapse columns was 25 m.(2)Study on Pressure Relief and Disturbance Failure around Collapsed ColumnsCollect on-site observation data and previous summaries for analysis.The periphery of the collapse column can be divided into three parts from inside to outside.(1)Disturbance and destruction section.During the collapse process,the collapse column will inevitably cause a certain degree of disturbance to the surrounding rocks,leading to the development of surrounding rock fractures;(2)In the affected section of pressure relief,as a collapsed body,the collapse column is composed of broken materials that are difficult to support normal ground stress.Therefore,pressure relief is inevitable around the collapse column;(3)The original intact section is the original normal rock stratum.(3)Field Study on Water Injection Pressure and Seepage LawConduct segmented drilling into the roadway and goaf,and conduct water pressure tests during drilling.Through monitoring with instruments such as pressure gauges and flow meters,the water pressure and flow rate during water pressure are obtained.The permeability coefficient of the rock in this section is calculated,and the relationship between water pressure and seepage is obtained.The original intact section of the roadway is divided into a distance greater than 20 m,a distance of 20-12 m for the pressure relief affected section,and a distance of 12-8m for the disturbance damaged section.The distance between the original intact section of the goaf is greater than 34 m,the distance between the pressure relief affected section is34-22 m,and the distance between the disturbance damaged section is 18-22 m.(4)Numerical simulation study on water injection test of collapse columnBased on the 7218 collapse column of Renlou Coal Mine,a collapse column model is established.The calculation shows that the closer the collapse column is,the smaller the normal stress of the crack and the larger the opening of the crack.A fixed flow rate is used to perform segmented water pressure on the cracks around the collapse column.When the water pressure and normal stress of the crack are the same,the water pressure stops.The flow rate after each stop of water pressure is calculated to obtain the water pressure flow rate around the collapse column.(5)Borehole water injection for detecting collapse columnAnalyze the feasibility of water pressure exploration for collapse columns,combined with the minimum development size of collapse columns in Renlou Coal Mine,the theory of pressure relief and disturbance damage around the collapse columns,the on-site water pressure test and numerical simulation results,and obtain the technical parameters and drilling spacing of 45 m for underground water pressure exploration of collapse columns.Using water pressure method to detect collapsed columns in Renlou Coal Mine.