厦门翔安大断面浅埋软土隧道 CRD 法开挖变形控制研究

摘要

厦门翔安海底隧道为富水、软弱地层大断面浅埋暗挖隧道，施工采用CRD法，CRD1部开挖引起变形约占总变形量的50％，采用CRD1-CRD3-CRD2-CRD4开挖顺序更有利于拱顶下沉总量控制，提出以拱顶下沉量为主要控制指标，控制基准值为200 mm；对于异常变形问题，提出采用调整导坑开挖顺序、分阶段控制变形、优化工法配套参数和支护参数，使超限变形得到有效控制，提高了施工月均进尺。%The Xiang'an subsea tunnel in Xiamen province of China is a water-rich,large-profile tunnel built on soft stratum and its construction applied the CRD shallow mining method .It is noticed that the 50% of the deformation took place at the excavation of CDR 1;therefore it is proposed that the construction follows the procedure of CRD 1-CRD3-CRD2-CRD4 , which is beneficial for the overall control of the arch top settlement .It is suggested that the arch top settlement should be used as the main control criteria, with the value set at 200 mm.In case of severe deformation, approches such as the adjustment of heading excavation order , the deformation control over stages , the optimisation of the auxiliary parameters in the construction methods and the improvement of the support parameters are used.As a result,the deformation is well managed and the construction process is accelarated .