Study on the Truss Support Technology for Coal Side in a Soft Broken Coal Roadway Under High Stress

The coal side deformation and sliding can not be effectively controlled by use of the traditional bolt or cable support in the high stress crushed surrounding rock and large section roadway. For solving this problem, the new prestressed truss support technology is put forward, and its supporting principles of roof and two walls are stated. The mechanical model of cable-channel steel truss is established, and then the tensile strength of the cable and the maximum deflection of the channel steel are derived. By way of field investigation, mechanics theory analysis and actual production condition, the scheme is defined and applied in the replacement roadway. Measurement results of surrounding rock behavior show that the coal side displacement is no more than 254mm and the roof convergence is less than 172mm. Apparent economic and technical profits have been achieved.