Meitan kexue jishu (Sep 2024)
Characteristics of deformation and failure of surrounding rock in roadway under strong impact load and control technology
Abstract
In response to the challenging problem of deformation and failure of surrounding rock and support structures in roadways under rock burst, a comprehensive research approach involving numerical calculations, field measurements, and laboratory experiments was employed. The study analyzed the characteristics of deformation and failure of surrounding rock and support structures in roadways under strong impact load, investigated the influence of impact load and mining-induced stress on the dynamic mechanical response of surrounding rock and support structures, developed impact-resistant support materials, and proposed a support-unloading coordination control technology, and selected typical rockburst mines for application. The research findings indicate that when the roadway roof is impacted, the maximum particle velocities of the roof, sidewalls, and floor are 1.41 m/s, 0.63 m/s, and 0.25 m/s, respectively. The surrounding rock on the advancing side of the roadway is most affected by the impact, followed by the lateral side, with the retreating side being the least affected. The combined effect of mining-induced stress and impact load results in a larger range of roadway damage, with the plastic zone area reaching 2.1 times the original rock stress. With increasing impact energy, the deformation and peak particle vibration velocities of the roadway increase sharply, and there is noticeable fluctuation in the force on the bolts (cables). Blast destressing has little effect on the anchoring force of the roadway sidewall bolts but significantly affects the anchoring force of the anchor cables, with an average reduction of 26.7% in anchoring force of the anchor cables. The yield strength of high impact toughness anchor rod is 800 MPa, the elongation at break is 20%, and the impact absorption energy is 150 J; The maximum force extension rate of the high elongation anchor cable is 8%, and the tensile strength is 1770 MPa. The coordination control technology was field-tested in a Kuangou coal mine, where the forces on the sidewall bolts ranged from 53 to 84 kN, and the forces on the roof anchor cables ranged from 122 to 219 kN, all within the safe allowable range. The shallow and deep separation layers of the roof have not occurred, and even in the event of a large energy microseismic event, the support system remained stable.
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