深井软岩高应力巷道过超大落差断层破碎带围岩控制技术

Surrounding rock control technology of overlarge drop fault fracture zone in deep soft rock high stress roadway

针对超大断层带围岩破碎软弱、自承载力低、应力场复杂和动力扰动等不良地质条件,提出了围岩改性+局部强化+主被动联合支护为主体的断层治理新技术,即超前注浆掩护,小循环注浆加固,反底拱局部底板强化等联合支护技术。通过数值模拟对不同支护方案进行比选,获得巷道最优支护参数。数值模拟验结果表明:随着支护强度的提高,锚杆索受力趋于均匀,承压拱范围逐步变大,承载能力增强,喷浆层最大剪力呈减小趋势,最大弯矩先减小后增大;围岩塑性区范围逐渐减小,塑性区分布位置由两帮、底板逐渐演变为两帮,面积减少了约75%。工业性试验结果表明,巷道围岩28 d后趋于稳定,最大顶板下沉量约15 mm,底鼓量约25 mm,帮部移近量约35 mm,围岩稳定性控制较好。

In view of the unfavorable geological conditions such as weak broken surrounding rock, low self-bearing capacity,complex stress field and dynamic disturbance, we propose a new fault management technology based on surrounding rock modification + local strengthening + active and passive combined support, which is the combined support technology of advance grouting cover, small cycle grouting reinforcement and local floor strengthening of reverse bottom arch. Through numerical simulation, different support schemes are compared and selected to obtain the optimal support parameters. The numerical simulation results show that with the increase of support strength, the stress of anchor cable tends to be uniform, the range of bearing arch gradually increases, the bearing capacity increases, the maximum shear force of shotcrete layer decreases, and the maximum bending moment decreases first and then increases;the plastic zone of surrounding rock gradually decreases, and the distribution position of the plastic zone gradually changes from two sides and floor to two sides, and the area decreases by about 75%. The industrial test results show that the surrounding rock tends to be stable after 28 days, the maximum roof subsidence is about 15 mm, the floor heave is about 25 mm, and the sidewall displacement is about 35 mm. The surrounding rock stability is well controlled.