| Coal is the foundation of our country energy, but the occurrence condition of coal resources is poor, more than 90% of the coal production comes from the underground mining. Along with the increase of mining depth and the deterioration of occurrence condition and mechanics environment of coal mining, coal structure, the basic mechanical behavior of rock mass and destruction features, and engineering response is complicated, the resulting coal mine safety accidents restricts seriously Efficient safety of coal mining.At present, in the country rock pressure monitoring data for the auxiliary system that is basis on the determination of mechanical properties of surrounding rock and is auxiliary of rock pressure monitoring data is becoming more and more attention to. Mining pressure appear not only guarantee the regular observation of working face production safety, but also verify the working face support selection, and optimize the up and down along the trough of roadway supporting technology. Safe efficient, therefore, to carry out the large mining height coal mining key technology research, as well as the initial mining working face in mine roadway surrounding rock physical mechanics test and stop drift mine pressure monitoring is of great significance for improving the rationality of the design of roadway support, ensuring the safety of roadway, reducing support costs and achieving high yield and high efficiency. At the same time it has important engineering value for guaranteeing our country’s coal industry sustainable development, safety and ensuring the security of energy supply.The working face roadway support design of Huang YanHui coal is rely on experience In the past, when there is a large mine pressure appear, it is applied to adopt this method Strengthening the support form in shallow and simple coal seam mining. But with the increase of mining height, drilling speed and deep mining, under the trend of supporting, only relying on experience to support cannot meet the requirements of production of safety. To maintain the stability of surrounding rock of roadway scientifically, therefore, needs urgently advanced supporting ideas. Firstly it should carry on the in-situ stress test to grasp the size and direction of tectonic stress near the mining area. At the same time it need test Physical and mechanical properties of surrounding rock of roadway. Only by familiar with the surrounding rock mechanics properties can put forward the scientific and reasonable supporting scheme. At the same time, the timely and effective mine pressure monitoring can master the mining and pressure regularity of Working face roadways and can also effectively test the effectiveness of roadway support system.This test is aiming at these problems, taking the 15107 island coal face as the research object, adopting site investigation and laboratory experiment mechanics, loose circle measurement, computer numerical calculation and field monitoring method and so on, fully mastering the physical and mechanical parameters of surrounding rock of roadway, fundamental data such as loose circle range of roadway, putting forward reasonable and effective supporting design scheme,achieving the following main achievements:(1)Using series of uniaxial compressive strength test, rock fracturing test and triaxial compression test, obtained the coal and rock uniaxial compressive strength and tensile strength of coal and rock and cohesion and internal friction Angle was, no. 15 coal uniaxial compressive strength of 13.834 MPa, the elastic modulus of 2914.80 MPa, Poisson’s ratio of 0.332, tensile strength of 0.86 MPa, 2.06 MPa cohesion, mo was found within 42.96 ° Angle; Backplane mudstone 70.71 MPa compressive strength, elastic modulus of 21586.91 MPa, Poisson’s ratio of 0.287, the tensile strength of 5.26 MPa, 17.48 MPa cohesion, internal friction Angle is 56.25 °.(2)Through field monitoring, the mining face roadway deformation and failure characteristics is embodied in four aspects. Whole section of roadway shrinkage, serious, and roof abscission layer of floor heave of roadway supporting component damage. It analyses the causes of the instability of roadway from three aspects on the strength of surrounding rock, stress of surrounding rock and supporting, puts forward it is the main cause of deformation of roadway that mining of roadway surrounding rock strength is lower and large disturbance, low stress environment complex and help department of roadway supporting strength.(3)Through the mining face roadway roof development track transportation tunnel in the loose circle tests, it founds three fracture zones.The width of the first fracture zone that adjacent to roadway roof is about 0.1 m; The second fracture zone bandwidth 0.1 m to 0.15 m and focuses on the roadway above the position of the 2 m or so; The third fracture zone bandwidth 0.15 m to 0.2m and focuses on the roadway above the position of the 2 m or so, Roof bolt length is 2 m, the leakage length is 100 ~ 150 mm, it is close to the roof of anchorage zone. In addition, as the working face advancing, roof cranny is expanding, in the 5 m of the working face and roof within 2 m, adds 5 more obvious fracture zones whose width is at about 0.05 m. Distance of working face roof above 5 ~ 15 m within the scope of article 3 ~ 5 m development 2 is about 0.05 m wide fracture zone, more than 5 m rock is relatively complete.(4) Roadway roof develop into two fracture zone, when it is not affected by mining. The width of the first fracture zone that adjacent to roadway roof is about 0.1 m; The second fracture zone bandwidth 0.1 m to 0.15 m and focuses on the roadway above the position of the 2 m or so, chain pillar for side 0 ~ 0.25 m away from the roadway surface crack development, anchorage zone is relatively complete, Therefore, according to the results of rock mechanics performance test and roadway loose circle detection results, the roadway support design optimization as follows: The length of anchor by 2.0 m increases to 2.5 m, from 20 mm diameter increases to 22 mm. The original anchor wooden pallets were cancelled. 120×120×8 mm arc steel tray was optimized for 150×150×10 mm disc steel pallet. sidewall cooperate with specifications 2000×88 mm steel ladder beam by the phi 14 round steel Q235, it is advantageous to the bolt load to the spread of the surrounding rock and increase the speed of increasing load. Sidewall of coal is broken with hollow grouting anchor cable. Reinforcement can be achieved on the surface of broken coal, slurry using slurry, grouting pressure 1 ~ 2Mpa.(5) Industrial test has been carried out in 15111 working face gateway, Monitoring results show Roof subsidence is 80 mm, the largest roof subsidence is 41 mm, minimum roof convergence rate, the maximum is 3.33 mm/d, the maximum deformation of Small coal pillar is 240 mm, the minimum deformation of small coal pillar is 50 mm, small coal pillar help nearer the rate up to 8.33 mm/d. Entity coal for maximum deformation is 130 mm, small coal pillar help minimum deformation is 10 mm, small coal pillar help nearer the rate up to 6.8 mm/d. it shows that the deformation of surrounding rock of roadway two with small coal pillar help is given priority to, small help deformation of two coal pillar deformation of 57.1% ~ 83.3%, but the small coal pillar help the overall deformation of roadway is not large, that determine the width of chain pillars is reasonable. |
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