Abstract:
Aiming at the large deformation and difficult control of the thick coal seam roadway under water-drenched conditions, the zoning damage characteristics of thick coal seam water-drenched roadway and the synergistic control mechanism of double arch zoning are studied by theoretical analysis, numerical simulation and field test. The water-rock interaction model of the thick coal seam water-drenched roadway is established, considering the damage of pore pressure on mechanical parameters of coal and rock mass. Combined with the Mohr-Coulomb damage criterion, a water-mechanical-damage coupling model of coal seam roadway surrounding rock is constructed, and the model is numerically carried out by the secondary development of FISH language. The stress-strain curve of the coal and rock reveals the zoning laws of “crushing zone, plastic softening zone and plastic hardening zone and elastic zone” in the surround rock of water-drenched roadway in thick coal seam, and obtains the damage range of roadway zoning. Accordingly, the zoning synergistic control mechanism of “high pre-stressed long and short anchor cables + bolting and shotcreting with wire mesh” is proposed. Among them, the short anchor cable increases the supporting strength of surrounding rock, forms a pressure arch with anchor, metal mesh and concrete spray layer, and improves the stability of shallow surrounding rock. The long anchor cable fully utilizes the self-bearing capacity of deep surrounding rock to control the displacement of short anchor cable, forms a pressure arch with larger influence range and stronger bearing capacity, and finally achieves the coordinated control of double arch zoning in surrounding rock. The distribution laws of displacement, stress and plastic zone of roadway surrounding rock without support and with different support schemes are simulated and compared. It is determined that the support scheme of “high pre-stressed long and short anchor cables + bolting and shotcreting with wire mesh” based on the zoning synergistic control of double arch has the best effect. The “double arch” zoning surrounding rock control technology was applied on site in a thick coal seam water-drenched roadway of a mine in Shanxi Province. The results show that the maximum displacement of roof and floor is 142 mm, and the maximum displacement of two sides is 83 mm. The deformation of roadway surrounding rock is effectively controlled.