Abstract: The roadway with soft rock has such problems as high ground pressure, strong rheology, and large deformation in deep coal mining in China, so the large supporting force is needed to stabilize the surrounding rock. The author has put forward a new technology with truss support, and the truss is made of eight 12^# double I-Beams. Each beam connects another beam with 390 mm×800 mm×30 mm welded steel plate and bolted connection. In laboratory the truss mechanical property about ultimate load and deformation has been achieved by the monitoring system with different combination with horizontal load and vertical load that is stepwise added. The results have shown that under the uniform pressure ultimate bearing capacity of the truss is 1 500 t, and the ultimate deformation is 12.18 mm; when the ratio of the vertical load to the horizontal load is 0.2, ultimate load of the truss is 900 t, and the elastic deformation limit is 26.3 mm; and the failure is the connection slide and the diameter shrinkage damage. Compared with the traditional U-shaped steel, the double truss support counterforce has been increased to 10 times. In the soft rock roadway, the author has put forward the first support with constant-resistance large-deformation anchor coupling support and reserved deformation; the support can release the deformation energy. After forming the anchor-surrounding rock coupling support circle, the strong truss force support has been used in the second support; this way can make full use of mechanical property. The truss structure may have an extensive application in fields of the deep roadway with the soft rock, high ground pressure and strong rheology in future.

Key words: soft rock roadway, double steel truss, full circle closed support, mechanics performance testing, roadway support