Rebar bolt optimization for large deformational roadways with application case
2019, Editorial Board of Journal of CUMT. All right reserved. In order to solve the problem of large deformation roadway support in Qianjiaying coal mine, a new bolt was designed according to bolt profile parameters, the determination of bolt anchorage failure mode and the analysis of anchor force residual strength. Based on the thick-walled cylinder theory of anchoring mechanics, the relationship between the strength of different surrounding rocks and the wall thickness of sleeves was studied, the anchoring force test was carried out on the designed new bolt and the conventional left-handed bolt of the coal mine through laboratory and on-site pullout tests. The experimental model of anchoring force test simulating the geomechanical conditions of Qianjiaying coal mine was established. The results show that the radial stiffness of the surrounding rock with elastic modulus of 10~30 GPa is consistent with the aluminum sleeve with wall thickness of 3~10 mm. The surrounding rock with modulus of 30~70 GPa has the same radial stiffness as the steel sleeve with wall thickness of 3~7 mm. The new anchor bolting force is 13% and 16% higher than that of the left-handed bolt in the coal mine, and the energy absorption capacity is increased by 15% and 55%.The anchoring effect is significantly improved, and it is more suitable for the bolt support of the large deformation mining roadway in Qianjiaying coal mine.