地铁盾构隧道下穿既有运营铁路施工风险评估

Construction risk evaluation of shield tunnel underneath an existing operational railway

针对盾构隧道下穿运营铁路工程的实际特点,对其施工风险因素进行了总结分析,建立了基于层次分析法的风险评价结构模型,并进行实例分析与工程应用。结果表明:依托工程下穿施工将存在极大的安全风险,主要风险源分别为因卵石自稳能力差、盾构施工注浆不及时和土仓压力控制不当造成地表沉降,为后续施工风险控制措施的制定提供了直接依据。

According to the actual characteristics of shield tunnel underneath an operational railway, the construction risk factors were summarized and analyzed, and then the risk evaluation model was put forward using the analytic hierarchy process, also example analysis and engineering application was conducted. The results show that the underneath construction of background project has huge safety risk, and the main risk factors were the ground surface settlement caused by the sand pebble stratum with poor self stability, shield grouting is not timely, and inappropriate earth pressure of chamber. This results can provide an direct basis for design the construction risk control measurements.