Determination of support parameters of the hottest

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Determination of support parameters of wall blasting mining face

I. selection of prop specifications. Single hydraulic prop is divided into internal injection type and external injection type. The internal injection type uses its own hand pump to suck the oil in the oil storage chamber in the column into the pump, pressurize it, and then input it into the working chamber to extend the movable column; The external injection type uses the liquid injection gun to inject the high-pressure liquid from the pump station into the working cavity of the pillar, so that the movable pillar extends out. Because the former has complex structure, large mass and slow support rising speed, the external injection single hydraulic prop DW prop is widely used at present. The specification of dw06-dw20 pillar is the pillar without lengthening section, and the maximum support height is 630-2000mm; With the increase of mining height, dw22 and dw25 pillars were developed after the extension was welded on the movable column. The maximum support height (2) was 2200mm and 2500mm respectively before the experiment. With the further increase of mining height, it is impossible to increase the length of the movable column extension. The extension is welded at the lower part of the oil cylinder, and dw28, dw31 and dw35 pillars are developed. The maximum support heights are 2800mm, 3100mm and 3500mm respectively, forming a dw06-dw35 single hydraulic pillar system

the maximum height of the pillar hmax=mmax-b+e, where mmax- the maximum mining height of the working face, MMB - the thickness of the top beam, Mme - in order to avoid the free stroke of the movable column left by the working face when the pillar is fully withdrawn, generally e=100mm. If there is a false roof that falls with mining in the direct roof and coal seam, the maximum height of the pillar should also consider the thickness of the false roof C, that is, hmax=mmax+c-b+e, the minimum height of the pillar hmin=mmin-s-b-a, where mmin - the minimum mining height of the working face, MMS - the average maximum subsidence of the roof at the maximum roof control distance, MMA - the unloading height of the pillar determines the maximum height and minimum height of the pillar, so the appropriate pillar specification can be determined on the pillar sample

II. Pillar layout. The layout of single hydraulic pillars in blasting mining face should be compatible with the occurrence conditions of coal seams and the properties of roof and floor, and conform to the characteristics of blasting mining. In addition to ensuring the safety of mining space operation, we should strive to reduce the workload of support

generally, the blasting and mining face adopts a cantilever support composed of a single hydraulic prop and an articulated top beam. For the convenience of pedestrians and operations, the pillars of the working face are generally arranged in a straight line. At present, the layout of pillars of blasting mining face mainly includes two kinds: straight beam columns and staggered beam branch line columns

the layout feature of the beam aligned straight column is that the beam ends are aligned along the direction of the coal wall, and the pillars are arranged in a straight line. According to the relationship between the cycle progress and the length of the top beam, it can be divided into two types: China is the first largest country of new energy vehicles, and the beam length is equal to the cycle progress length and the beam length is equal to twice the cycle progress length

when the beam length is equal to the cycle progress length, 20Hz hanging beams are used for each cycle progress along the working face, and the pillars are generally positive cantilever pillars. This kind of pillar layout is simple, the specification and quality are easy to control, and the top line is neat, which is convenient for organization and management. When the cycle progress is 0.8m and 1.0m, this layout is generally used. However, due to the large cycle progress of this arrangement, each support along the working face needs to be hung with beams and supports, so it takes a long time to blast and drop coal. Therefore, it should not be used under the conditions of soft coal seams and poor roof stability

when the length of the top beam is twice the cycle progress, if all positive cantilever pillars are used, 2 Gan Yong made a special report on the development of 1035 new energy materials, and hung the beam once a cycle, with temporary supports for each support in each cycle. In the second cycle, hang the beam and change the temporary pillars into permanent pillars. Because there is no beam hanging in the first cycle, timely support can not be achieved, the distance between the top of machine control is large, and the roof is easy to collapse. In addition, the workload of workers is uneven. This arrangement is less except when the roof is particularly stable

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