某地铁盾构区间块石处理方法

武汉市轨道交通机场线工程土建工程盾构区间块石密集,对盾构施工有较大影响,为确保隧道施工顺利开展,采用以弹性波CT检测为主,地质钻探为辅进行块石探测。对于小直径(1.5 m以下)块石优先采取旋挖钻对块石冲击破碎进行预处理,大直径块石采用冲击钻孔破碎、开挖竖井方式将块石掏取出来,若冲击破碎无法达到预期效果,则采用深孔爆破等方法处理,块石地面预处理过程中如有未发现的块石,采用盾构机破岩直接通过;根据详勘及补勘结果,采用复合式土压平衡盾构机进行掘进,选用国产刀具,刀盘装配全盘滚刀用于破碎块石,考虑到刀盘开口率及其地层因素,滚刀间距控制在100 mm,严格控制盾构机在块石地段掘进时的盾构参数。实践表明,该方法取得了较好的施工效果,具有一定的指导与借鉴意义。

Treatment Method of Block Stones in a Metro Tunnel Shield Section

Dense block stones are concentrated in the civil engineering shield section on Wuhan Urban Rail Transit Airport Line,which imposes a great influence on the shield construction. In order to ensure the smooth construction of the tunnel,elastic wave CT detection is employed and supplemented by geological drilling to detect block stones. Rotary drilling is used to handle small diameter stones less than1. 5 m in diameter,while impact grinding is used to beak large diameter stones,which are extracted from vertical shaft. Deep-hole blasting is conducted if impact grinding fails. During pretreatment process,the shield machine comes to break through directly if block stones remain undetected. According to detailed survey and supplementary survey results,the heavy industry composite earth pressure balance shield machine is called for excavation. Domestic cutting tools and cutter head with full hob are in service to break block stones. Taking into account the cutter opening and its formation factors,hob spacing is controlled at 100 mm,and shield parameters are strictly controlled when the shield machine works.Practices show that the method is effective with certain guiding and referential significance.