泥水盾构下穿堤防的风险分析及控制研究

 采用泥水盾构法在软土地区修筑水底隧道时，不可避免地要穿越堤防。对泥水盾构穿越堤防的风险源进行系统分析，阐述风险产生的原因、造成的危害及规避和处理措施，并结合杭州庆春路过江隧道泥水盾构穿越钱塘江南岸大堤的工程实例，验证所述风险控制措施的合理性及可行性。分析表明，优化的泥水盾构掘进参数控制，主要包括合理的切口泥水压力设定、良好的盾构姿态控制、及时有效充分的盾尾同步注浆等、外部不利条件的避免，如持续降雨、江河汛期、堤防顶面道路车辆荷载等、实时精准的监测，详实可行的应急预案的制定等，可以降低或规避泥水盾构穿越堤防的部分风险，以确保堤防结构及施工安全。

RISK ANALYSIS AND CONTROL FOR SLURRY SHIELD UNDER-PASSING EMBANKMENT

It is inevitable for the slurry shield to under-pass the embankment in construction of under-river tunnels in urban areas. For the safety of both the embankment structure and construction，resources of risks when slurry shield under-passing the embankment are analyzed in detail，and their causes，impacts and mitigation measures are also studied accordingly. The case history of risk control for slurry shield under-passing the embankment in Hangzhou Qingchun road cross-river tunnel in China confirmed the rationality and feasibility of the suggested risk control measures. Through optimization of slurry shield driving parameters，avoidance of adverse external conditions，in-time monitoring，and setting of detailed emergency countermeasures，some of the risks encountered during slurry shield under-passing the embankment can be reduced or mitigated so as to insure safety of the embankment and construction.