盾构法施工海底隧道孤石及基岩侵入体爆破施工风险分析

Risk Analysis on Blasting of Boulder and Bedrock Intrusion in Sea-crossing Tunnel Bored by Shield Machine

针对复合地层中,开挖断面内局部高强度基岩及孤石侵入体,盾构自身刀具无法有效破岩施工难点,在综合分析地面引孔下药施爆的控制钻爆法,控制破碎碴块体量基础上,对爆破产生的影响因素进行系统归类,建立孤石及基岩侵入体爆破施工风险综合评价指标体系,并结合层次分析法和模糊集法分别确定各级因素权重及隶属函数,评估其风险接受等级。实践证明:在设计和施工上采取合理的措施后,基岩及海域孤石地层预爆破风险评估切实可行的,风险规避措施有效。

The rock breaking efficiency of cutter tools of shield machine is low in complex stratum with local high intension bedrocks and boulders.The controlled drilling and blasting method and controlled broken rocks are synthetically analyzed.The influences induced by blasting are systematically classed.The evaluation system of blasting risks of boulder and bedrock intrusion is established.The factor weight and membership function of each risk grade are determined by means of APH method and fuzzy method,so as to estimate the risk acceptable grade.The practice shows that the mentioned methods are reliable and effective.