Research Of Soft Rock Roadway Supporting Technology In Mukong Colliery

Based on the background of mine soft rock roadway construction with Mukong coal mine in Guizhou. Supporting the cause of the original mode of transport trough +700 failure of theoretical analysis. Presented based on the truss anchor combined supporting technology.Mukong Coal mine tunnel roof poor stability, low strength, easy weathering and disintegration. Gateway with bolt anchor and steel band support, because of the design parameters is unreasonable and supporting strong enough, poor construction quality. As a result, the roof bolt and cause a serious failure of the tray support、beam with damage such as broken and twisted behavior occurs. Because in the past the roadway excavation, underground rock in triaxial stress equilibrium, after excavation of the balance system would be broken on the new distribution adjustment of roadway surrounding rock stress. Stress state of surrounding rock of roadway becomes two dimensional stress state of surrounding rock intensity to low. For +700 transportation roadway, because of the low intensity of roadway surrounding rock while under the influence of mining dynamic pressure, deformation and failure of surrounding rock of roadway. In addition, as after the roadway excavation, not timely support preload preload or strong enough, just a natural tunnel roof composite beam, can not play the role of composite beams. Especially in soft rock roadway, if not promptly applied for a certain amount of preload bolt and cable anchor, can not play its role in supporting the initiative. Only when the roof strata deformed to a certain amount of time, it has a carrying capacity, then separation and tunnel roof has been destroyed, surrounding rock bearing capacity is greatly reduced.Through complex analysis and study on elastic rectangular tunnel surrounding rock stress. Based on +700 haulage of engineering geological information, establish FLAC numerical model. Analysis of deformation under different aspect ratio and lateral pressure coefficient rectangular roadway, according to the actual situation of reasonable size to determine the roadway.Compared to ordinary prestressed truss anchor cable, a smaller radius and depth of its impact in the axial direction, the stress state of rock change is weak, so the proposed truss anchor support technology. It can effectively make the neutral axis close to the tunnel roof surface, reducing roadway slate roof beam tensile stress area, increasing the compressive stress area, effectively improve the stress state of rock, reducing the anchorage zone of rock beam due to tensile stress generate instability, collapse accidents, improve the overall roof rock roadway carrying capacity. The prestress truss cable truss connectors, high strength steel strand, anchors, reverse unit and other components.Prestress truss cable anchorage point is formed in deep rock roadway shoulder pit two similar inverted wedge, by tension steel strand prestressed transfer to surrounding rock of roadway roof. When the roadway when subjected to dynamic loading effects, "ladder" cards in two corners of the surrounding rock of roadway roof above and more pressure, "ladder" stuck tight formation at two corners at the base above the tunnel roof bearing arches. Prestress truss cable in horizontal and vertical directions at the same time on the surrounding rocks of roadway roof providing pressure stress, makes the rock inside the anchorage zone in biaxial stress state. It produces active supporting force to make the tunnel roof has moved vertically upward trend, effectively prevent the roadway roof separation.By FLAC numerical simulation method research +700 haulage different truss of prestress truss support plan of anchor cable and anchor anchor cable length, cable diameter and vertical angle, orifice and distance in roadsides, of anchor prestress along with roof bolt density then analyzed by SPSS poor orthogonal experiment. Finally, through the transport trough surface displacement monitoring, the outcome of +700 transport trough in prestressed girder truss anchor supporting schemes roadway control effect, less deformed roadway stability, achieve the desired results.