The Mechanism Research Of Preventing Heading Face Gas Outburst By Hydraulic Cutting Seam

At present, Coal and gas outburst coal mine is one of the largest accident harm degree in China, and a lot of all outburst take place in the heading face of coal seam, most coal seam in China is the coal seam which has very poor permeability, the former methods such as intensive drilling drainage, hydraulic punching, hydraulic crack, mining liberation drainage layer strengthening which were used to improve the low permeability of coal seam permeability character, but the effect of gas drainage is not quite well in the endo In recent years, through the research relevant to the permeability coefficient of coal, Coal seam of itself suffer the influence of buried depth which is one of the factors, ground stress and its own stress characteristics of coal will influence the permeability of coal, Professor through the related theories and experiment research, think that "Discharging pressure is the only effective technical way that can effectively improve the characteristics of low permeability of coal seam "[1]oAlthough,from the1970s to the present, many cut coal seam hydraulic pressure relief test has been marched, but hydraulic cut seam coal whether to affect the stability of surrounding rocks makes roof-floor after heading face, and seam roadway and tunneling of the two gas pre-drawing aspects for migration after cutting, further research haven’t appeared in current domestic, and is always a unanswered question.High pressure hydraulic cutting technology can effectively solve gas drainage problems of low penetrative coal seam, is the main technical method to avoid or reduce the coal and gas outburst dynamic disasters, etc. This article is about implementation hydraulic cut split to the heading face using high pressure hydraulic push of directional drilling rig, which makes the coal seam roadway discharging pressure, the number of the fissures and coal seam crack significantly increased after cutting, so not only enhance the rate of gas drainage, at the same time improve the low permeability permeability of coal seam, to a great extent, prevent gas outburst, and greatly improve the condition of the coal mining disorders.I am under the long-term guidance of Professor, for the foundation of applicating of numerical simulation of the software engineering of FLAC3D, in view of some related research through the hydraulic cut of coal seam heading face top floor and wall, the stability of the two help influence and seam coal seam gas migration cut after hydraulic cut of coal seam, the conclusion has the vital significance in coal and gas outburst of safety and efficiency. This article mainly do some research from the following several aspects:(1) Using the technology of high pressure hydraulic cut seam, and taking various of cutting seam height, by means of the numerical simulation, analysing the situation of seam coal and rock seam groove around the stress and deformation after cutting,through calculating and comparison analysis, ensure make coal seam around slot to the largest extent discharging pressure completely by cutting seam of30mm height in the end(2) Taking some height of hydraulic cut seam, which is on the basis of making the greatest degree of coal seam around slot discharging pressure, and on the basis of the coal seam roadway excavation tunneling of the slot of5m distance later, the stress distribution and around roadway deformation and return to the new balance, of left right side appeared in the vertical stress concentration, and the stress concentration appear below the level, peak reached14MPa, roadway deformation to3cm above the biggest, JueJinTou support ahead of the present three pressure stress change rule.(3) Use of coal seam RTEA2D software to cut the gas emission after seam and gas pressure conditions changing numerical simulation seepage calculation, according to the mining project of gas pressure requirements in less than0.74MPa index set, to prevent the seam hydraulic cut groove heading face gas outburst mechanism and effect to give proof and explanation.(4) Putting forward to the process technology solutions that is used to prevent heading face gas outburst, and monitoring the whole of the roadway seam gas concentration changing in the process of high pressure hydraulic cut after cutting, through the seam roadway flow in the body and two ahead for coal gas migration after cutting, and in the process of gas emissions coal gas pressure changes, the test of permeability of coal seam after cutting, to checking the effect of preventing the heading face gas outburst through hydraulic cutting seam.