| Since 1987,Located in the Huanghuai area in central my country,a large number of coal mine shafts have been damaged and deformed.There are huge hidden dangers in the normal operation and safety of coal mines.The shaft is the throat part of the mine.It is the only passage for coal mines to the ground,transporting materials and staff,and plays a vital role in the coal mine safety guarantee system.Therefore,the research and analysis of the damage mechanism of the shaft wall with similar geological conditions is of great significance to the safe production of coal mines.This article is based on Huaibei Mining Group's Linhuan East Air Shaft Wall Crack Repair and Reinforcement Project as a background to study it.Using ANSYS numerical simulation software to establish a model,calculate the vertical stress,equivalent stress and surface settlement of the shaft wall after the pressure relief groove is opened in different positions under the four-containment drainage condition of the east air shaft of Linhuan Coal Mine to determine the location of the pressure relief groove After this,calculate the vertical stress,equivalent stress and surface settlement of the well wall after opening different numbers of pressure relief grooves near the junction of the topsoil layer and the bedrock section to determine the number of pressure relief grooves.The results show that the pressure relief groove is set at 222 meters near the junction of the topsoil layer and the bedrock layer,and the pressure relief effect is the best.The vertical stress and equivalent stress of the shaft wall are both less than the calculated results at 190 meters and 240 meters;The single pressure relief groove and the double pressure relief groove have close to the stress concentration release degree at the interface of the bedrock.The maximum vertical stress of the shaft wall is only reduced by 0.7%,and the repair effect is relatively small,and it is considered that the shaft wall has been broken at-218m,Relieved part of the stress concentration,combined with the comprehensive consideration of engineering safety and economy,this repair is preferably set up a pressure relief groove at-222m,which can meet the safety requirements of the wellbore.According to the numerical calculation results and the scope of the shaft damage,the shaft repair and reinforcement design and construction plan are proposed,which mainly include grouting between and behind the shaft wall.Grouting reinforcement is carried out from the vertical depth of 212m to 227m,and the total grouting section height is 15m.;At the vertical depth of 222 meters,set a pressure relief groove with a size of 300mm × 600mm;and at the vertical depth of 218m?223m,the total height of the inner shaft wall reinforcement section is 5m,and a total of 20 gauge channel steel shaft rings are erected 25 channels.After the wellbore was treated by technical means such as opening pressure relief grooves and grouting behind the wall,the safety performance of the well wall was greatly improved.After 10 months of on-site monitoring,the wellbore was in a safe state.The research results of this paper have guiding and reference significance for the mines whose shaft walls are damaged due to drainage settlement in the Huanghuai area in the future.Figure 60 table 10 reference 72... |
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