Optimization Of Roadway Support Design And Selection

The control of the stability of the roadway surrounding rock in coal bed with large inclination angle must adopt the key part coupling support technology, i.e., on the basis of the symmetrical support of ordinary anchor net rope, the key parts of the roadway surrounding rock that produce differential deformation damage are strengthened to support, so as to make the deformation between the support body and the surrounding rock coordinated, to maximize the role of the support as well as the self-supporting capacity of the surrounding rock, and to achieve the integration of the support and load homogenization to achieve the purpose of the roadway stability. Uniformity, to achieve the purpose of roadway stability.

According to the characteristics of the coal seam, the asymmetric coupling control technology of “anchor mesh beam+anchor cable+bottom angle anchor” is adopted, namely:

(1) Adopt "anchor rods + higher stiffness steel mesh or W-type steel belt coupling support to improve the integrity and increase the strength of surrounding rock.

(2) Use anchor cable to strengthen the coupling support for the key part of damage, eliminate the interlayer shear slip deformation, and at the same time, mobilize the strength of the deep surrounding rock to reduce the vertical stress of the roof plate in the bottom plate stress concentration.

(3) The bottom angle anchor with larger stiffness is used to strengthen the coupling support for the key part of the obtuse angle damage of the bottom plate, to transfer the plastic slip force of the bottom expansion, and to reduce the bottom expansion force.

Specific support form: 

mainly adopts φ21.8 high-strength pre-strength anchor cable. According to the principle of asymmetric force on the top plate and two gangs of inclined coal seam, the arrangement of anchor rods and anchor cables is optimized, and the gangs are supported by anchor cables, and the details are as follows: the top anchor rods still adopt φ22×2500mm left-handed threaded steel high-strength anchor rods to support with the “W” steel belts, and the special washers for the ‘W’ steel belts are used to support the “W” steel belts. W“ steel belt special shims are replaced with stronger butterfly shims, and the row spacing between the anchor rods is 800×800mm, and the gang anchor rods are still φ20×2000mm left-turned threaded steel high-strength anchor rods with ‘W’ steel belts for support, and the anchor rods shims are ”W" steel belt special shims. "The anchor ropes are all replaced by φ21.8×8300mm 19-strand low relaxation strand anchor ropes, and the top anchor ropes are 3/1.6m, which are not arranged symmetrically according to the centerline of the roadway, but the 2 anchor ropes close to the lower hand gang are all moved to the lower hand gang according to the pressurized condition, and all of them are constructed at an angle to ensure the anchor ropes are in the same position as the anchor ropes. The construction with angle ensures that the support of anchor cable can play a better role. Gang part in the original anchor support on the basis of joining the gang anchor cable support, every 2.4m arrangement of a group of gang anchor cable each group of 4, two gangs of 2, gang anchor cable for φ21.8 × 4300mm 19 strands of low relaxation strand production of anchor cable with 300 × 300 × 16mm steel plate and locks for tensioning, gang anchor cable near the top part of a distance of the roof 1.2m, the second from the first root of 1m. The spacing of the second one from the first one is 1m.