Research and Application of Low Density Roof Support Technology of Rapid Excavation for Coal Roadway

The mismatch of speed of mining and excavating is the main contradiction of high efficiency production in China, improving the excavating speed of coal roadway is an effective way to solve the problem. According to the engineering geological conditions of the main haulage roadway 21205 in Hulusu Coal Mine, the technical problems existing in the original support scheme were analyzed, increased the excavating speed of roadway through improve support efficiency of single bolt and reducing density of bolt, a rapid excavation technology based on anchoring method of critical high efficiency and low density on roof of coal roadway was proposed. The influence of different bolt length and different pre-tightening force on the stability of roadway roof was studied by FLAC3D simulation, the results showed: (1) increasing the length and pre-tightening force can control the development of the roof vertical strain with a certain range; (2) as the length of bolt increases, the compressive stress zone of the rock layer between the two bolts increases and the compressive stress in the rock layer area of the anchorage section tends to increase; (3) with the increase of pre-tightening force, the effective, compressive stress zones between the two bolts overlap with each other, forming a whole, and the compressive stress values in the near zero stress zone increase. Decided the scheme that, bolt length is 4 m, pre-tightening force is 200 kN, and the support density is 0.5 root/m(2), industrial experiments were carried out. The mine pressure monitoring showed that the roof of the roadway has almost no ionosphere, and the deep ionosphere was well controlled. The monthly excavating progress of the roadway was increased from 520 to 825 m, with a rise of 58.7%, the technical and economical effects were significant. It was proved that the scheme is in line with the actual. It can provide reference for roadway rapid excavating support technology for similar conditions.