大断面巷道中空预应力注浆锚杆的支护效果研究

针对金川矿区大断面巷道在强构造应力作用下围岩变形严重的情况，提出了中空预应力注浆锚杆的支护工艺。通过数值计算得出以下结论:相比传统的普通砂浆锚杆支护工艺，采用中空预应力注浆锚杆支护工艺能够主动加固围岩，提高支护刚度；巷道两帮的变形减小了约14.56%，最大、最小主应力分别降低了4.4%和7.2%，粘结层破坏范围也随之减小。通过对支护后巷道变形监测发现:两帮最终变形量减小了约36.6%；通过抗拔实验，中空预应力注浆锚杆的抗拔力达到140kN，远大于普通砂浆锚杆的40kN抗拔力，中空预应力注浆锚杆有更好的支护效果。

Study on support effect of hollow pre-stress grouting anchor in large section roadway

Aiming at the serious deformation of surrounding rock under strong tectonic stress in large section roadway of Jinchuan mining area, the support technology with the hollow pre-stress grouting anchor was put forward. Through numerical calculation, the following conclusions were drawn. Comparing with the traditional supporting form with mortar bolt, the surrounding rock is passively reinforced and the support rigidity is enhanced by the support technology with the hollow pre-stress grouting anchor. The deformation in two-sides of the roadway are reduced by 14.56%, the maximum and minimum main stress are reduced by 4.4% and 7.2% respectively, and the damage range of bonding layer is decreased. According to the monitoring results on deformation of the roadway after supporting, it showed that the final deformation of the two-sides is reduced by nearly 36.6%. Through anti-pulling test, the pull-out resistance of hollow pre-stress grouting anchor is up to 140 KN, which is far greater than that of ordinary bolts, being as 40KN. The hollow pre-stress grouting anchor has better support effect.