Abstract: In order to study the truss-cable combination support mechanism in the large mining height and complex roof open-off cut, adopting theoretical analysis, field measurement, numerical simulation test method, the truss-cable support parameters in the open-off cut of large mining height 2-1101 working face were optimized. The results show that if the inclination of anchor cable is too large or too small, these are not conducive to control the deformation and plastic zone of the surrounding rock. The anchor cable inclination angle of 65°~75° is the best for truss-cable support; anchor points in the truss system must be anchored into a stable rock pressured to ensure that the truss system has a stable anchoring basis point. Truss-cable drilling depth is chosen as 9 m to enhance the stability of the roadway. The reasonable distance value of the cable drilling to roadway side is 1.5 m. It is better to control the development of the surrounding rock plastic zone when the roof bolt density is 10 in each row. The results of field measurement show that the convergence rate of roadway section is very small. The largest value of the open-off cut two sides moving closer is 145 mm. The roof subsidence maximum is 166 mm; trussanchor- combined support has a good effect on the controlling of surrounding rock in the open-off cut.

Key words: large mining height, recombination mudstone, open-off cut, truss and anchor cable