城市轨道交通复杂环境下明挖区间控制爆破技术——以徐州轨道交通1号线一期振兴路站-徐州东站明挖区间为例

Controlled Blasting Technology for Cut-and-cover Metro Tunnel in Complicated Environment: Case Study on Running Tunnel from Zhenxinlu Station to Xuzhoudong Railway Station of Line 1 of Xuzhou Rail Transit System

为了在自身地质条件复杂,且外部存在交叉作业、无法实施封闭爆破施工的条件下,控制露天爆破振动及飞石对周边构建筑物的影响,以徐州轨道交通1号线一期地下市政工程振兴路站-徐州东站明挖区间爆破控制为例,采取减震带措施降低振速35%;主爆区通过严格控制同响最大装药量,合理布设炮孔和设计装药参数,使炮眼利用率超过90%;边坡采用预裂爆破技术成型较好,残眼率85%,超挖不超过15 cm;采取堵塞覆盖措施,有效控制了爆破飞石;通过联合警戒防护,避免了交叉施工、人群车辆繁多的风险;历时6个月开挖完成20万m3,取得了良好的进度、安全和成本效益。结果证明所采用的技术方法合理、安全,能够确保邻近高层建筑物的安全。

The running tunnel from Zhenxinlu Station to Xuzhoudong Railway Station of Line 1 of Xuzhou Rail Transit System is constructed by cut-and-cover method. The running tunnel is located in complicated geological and surrounding environment, therefore controlled blasting is carried out to minimize the impact of the vibration and flying stones on the adjacent buildings. Vibration zone is arranged , which reduces the vibration velocity by 35% ; the maximum quantity of single blow in the main blasting zone is strictly controlled and the blast hole parameters and the parameters are properly determined, technology is adopted for the slopes, which ensures more than 90% blast hole utilization ratio; pre-splitting charging charging blasting which ensures 85% blast hole trace ratio and less than 15 em overbreak; effective stemming and covering measures are taken, which brings the flying stones under effective control; comprehensive warning and protection measures are taken, which minimizes the safety risks on the surrounding environment. In the end, 200 000 m3 rocks have been excavated within 6 months, and satisfactory construction progress, safety and cost efficiency have been achieved. The practice shows that the technologies adopted are rational and effective.