新建隧道长距离平行近接既有地铁施工风险控制研究

RESEARCH ON RISK CONTROL OF NEW TUNNELS IN LONG-DISTANCE PARALLEL PROXIMITY TO EXISTING SUBWAYS

为了保证新建隧道长距离平行近接既有地铁的安全施工,采用层次分析法(AHP)研究了某工程的主要风险,并比选了不同注浆方案综合效果,结合现场监测对拟定的加固措施进行的验证,结果表明:(1)对于新建隧道近接侧穿运营地铁工程:近接风险(S 1)>自身风险(S 2)>工程地质(S 3)≈水文地质(S 4),即施工中应首先考虑近接施工对于既有运营地铁线路的影响,其次是施工自身风险。(2)3种方案的综合效果:注浆2 m方案>注浆3 m方案>注浆4 m方案,推荐该工程采用注浆2 m的加固方案。(3)现场采用深孔注浆加固方案后,新建隧道安全施工通过该区域,既有运营隧道监测指标均小于安全阈值。优选出的控制措施保障了长距离平行近接施工的安全稳定。

For the safe construction of new tunnels in long-distance parallel proximity to existing subways,major engineering risks were studied by the analytic hierarchy process(AHP).Comprehensive effects of different grouting schemes were compared.The proposed reinforcement measures were verified in conjunction with on-site monitoring.Results show that:(1)For new tunnels in proximity to subways in operation:proximity risks(S1)>construction risks(S2)>engineering geology(S3)≈hydrogeology(S4),so the impact of proximity construction on existing subways in operation should be considered first during construction,followed by construction risks;(2)Comprehensive effects of three schemes:2m grouting scheme>3m grounding scheme>4m grouting scheme,so the reinforcement scheme of 2m grouting is recommended for the project;(3)When reinforcement by deep hole grouting is applied on site and safe construction of new tunnels is performed,the monitoring indicators of tunnels in operation are below the thresholds.The preferred control measures can ensure the safety and stability of longdistance parallel proximity construction.