Support Crushing Research On Prevention Technology Of Overhead Concentrated Pillar In Shigetai Coal Mine

A large number of mine engineering practices have shown that the work surface is more prone to support crushing events when the coal pillars are overlaid,which seriously threatens the life and property safety of the mining enterprises and the normal production of the working face.Therefore,if effective stamping prevention measures can be taken,the working face can be safely passed through the overlying concentrated coal pillar area,which not only ensures efficient production of the working face,but also avoids casualties and reduces economic losses,so it is of great significance to mining companies.In this research background,the Shigetai coal mine is used as an engineering example,and similar simulation and numerical simulation methods are used to combine the measured ore pressure data of the 31201 working face of Shigetai Coal Mine to establish a similar and numerical model for experimental research.A comprehensive analysis of the mechanism of the support crushing produced by the 31201 working face over the overlying concentrated coal pillar was carried out,and the corresponding support crushing prevention and control measures were proposed.First of all,it can be seen from the field measurement that when the coal seam is concentrated on the working face,the working resistance of the hydraulic support increases sharply and the mine pressure appears strong.Secondly,the results of similar simulation and numerical simulation show that the working face of the underlying 3-1 coal seam31201 is 31 m,the initial pressure step is 13 m,and the working face is at a distance from the concentrated coal pillar.When the left boundary is 11 m,the overburden movement begins to be affected by the concentrated coal pillar,and the impact range is 52 m.During the process of overlying the concentrated coal pillar,the working step increases the pressure step,and the pre-support pressure increases continuously.The stress concentration phenomenon in the column area is also becoming more and more obvious.When the coal pillar is about to be overlaid,the pre-support pressure value reaches the maximum,which is 6~7 times of the normal value,which exceeds the bearing capacity of the roof andproduces shear in the roof in front of the working face.Destruction,causing the longitudinal crack below the coal pillar to develop and penetrate with the working face,the overlying rock layer is cut off as a whole,resulting in a strong impact ground pressure,resulting in a support crushing event;after the working face is covered with concentrated coal pillars,in the concentrated coal pillar area The accumulated high energy is released,the stress concentration range is reduced,the concentrated stress value is reduced,and the cycle step is basically 12 m.Finally,it can be concluded from the analysis of the support crushing mechanism that if the collapse of the basic top of the two layers of coal coincides,the high concentration stress will be released instantaneously,and a strong dynamic load will be transmitted to the lower working surface,resulting in support crushing.So controlling the rotary motion of the key block is the key to controlling the support crushing.Therefore,from the two aspects of urging the key block to advance in advance and avoiding its rotation,after the working face enters the influence range of the concentrated coal pillar,the two corresponding pressure frames are used to weaken the concentrated coal pillar in advance and accelerate the advancement speed of the working face.Disaster prevention measures can effectively avoid the occurrence of support crushing accidents.