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Investigation on Protection Scope Demarcation of upper Protective Layer Using Pitching Oblique Mining Method

Author: YuanZhiGang
Tutor: WangHongTu
School: Chongqing University
Course: Safety Technology and Engineering
Keywords: Steep Seam Mined deep false The protective layer The scope of protection
CLC: TD32
Type: Master's thesis
Year: 2008
Downloads: 247
Quote: 4
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Abstract

With increasing depth of underground mining, mining in the Southwest low air permeability and high gas outburst in coal seams, coal and gas outburst in coal mine production safety is a serious threat to natural disasters, and the protective layer is to prevent exploitation of the most effective and most economical prominent regional outburst prevention measures. Protective layer mining key is to determine the scope of protection, especially for the steep ramp on the bow pseudo Protection Seam scoping problems encountered even greater. The use of the traditional \This coal mine east of forest overlooking the steep upper protective layer is oblique mining research background, a protective layer on the steep bow oblique layer of protection scoping issues, the main contents include: (a) by post-seam mining plate stress, deformation, damage patterns and gas migration law were analyzed for field testing and numerical simulation analysis theoretical foundation. Analysis showed that: With the advance of mining face, floor rock stress experienced highly concentrated before harvest, postharvest sharp relief and stress recovery in three stages, corresponding to the compressive deformation before harvest, postharvest swelling deformation and deformation recovery; compression zone and the expansion zone at the junction, rock bottom shear failure-prone, and expansion is easy to produce separation with rock fissures and vertical fissures; tendency on the coal seam dip is the impact of changes and floor rock mass stress failure modes important factors: on the gently inclined and seam, seam floor next pass near the stress greater than the upper Yamaguchi, Yamaguchi near the lower plate is developed fissures; while for steep seam, down to the Ministry of gangue caving goaf play a major role in filling , limiting the expansion of the lower floor and the formation of cracks, fissures caused by the upper than the lower part of the mining development. (2) under the guidance of the theoretical analysis of the protective layer Donglin coal mining after deep false protective layer of gas pressure and flow changes on-site measurement and analysis of the gas pressure, flow and permeability coefficient with face advance variation of the distance obtained by the protective layer of the original distribution of gas pressure and gas pressure changes \Studies show that: Steep protective layer deep false face on the tendency of relief along strike throughout protection angle was non-uniform distribution, and its size is 43.5 ° ~ 53.6 °, along the direction of the lower pressure relief angle of inclination 78.7 °, the protective layer of not less than 3.4 times the distance ahead of the interlayer spacing. (3) using three-dimensional fast Lagrangian method, by simulating a protective layer on the Donglin coal mining after deep false protective layer of stress and deformation fields of the dynamic development process, identified as a protective layer on the face of the advancing , is the protective layer of the vertical seam bedding plane normal stress and deformation; under a protective layer on the stress relief after mining and coal law protection standards to protect the deformation criterion to determine the upper protective layer along the strike and dip of the scope of protection. Studies show that: the protective layer along the deep false tendency mining method, the lower boundary of the relief angles are 81.5 ° and 74 °; along the strike of the relief angle tendency was non-uniform distribution, the size of 30 ° ~ 52 °, pseudo-inclined face relief angle toward the middle of the largest, is 52 °. And site visits comparison, results of numerical simulation results with site visits and variation in value on both a strong consistency, indicating that the numerical simulation method to study the steep incline of the protective layer to protect the pseudo range is feasible. (4) comprehensive field test and numerical simulation results, and ultimately determine Donglin coal Steep bow oblique upper protective layer along the dip angle of the lower boundary of the relief 74 °; along the strike of the relief angle tendency was non-uniform distribution, size is 30 ° ~ 53.6 °, for safety reasons, according to a 30 ° angle toward relief plan to be protective layer, protecting direction has been extended again 5m; while the protective layer of not less than 3.4 times the distance ahead of the interlayer spacing.

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CLC: > Industrial Technology > Mining Engineering > Mine the pressure and support > Rock pressure and rock movement
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