【作者】 王湛；

【导师】 王立忠；

【作者基本信息】 浙江大学 ， 岩土工程， 2013， 博士

【摘要】 随着地质条件和施工条件沿隧道纵向的变化,在软弱地层中隧道都会产生纵向不均匀沉降。隧道纵向不均匀沉降会使隧道混凝土管片局部应力过大,而导致隧道管片的开裂、螺栓屈服以及接头张开错开等问题,进而使隧道接头处漏水,甚至漏泥。长此以往,会大大影响隧道的正常使用,甚至威胁隧道本身结构的安全。因此,为了保证软土中隧道的安全运营,对隧道不均匀沉降的产生原因以及造成的结构问题进行研究具有重要的意义。近年来,对于隧道纵向沉降的研究逐渐增多,但现有的研究大多集中在施工期盾构的沉降及对周边环境影响、隧道长期沉降规律、隧道衬砌设计等方面,而对导致隧道纵向沉降的原因、隧道纵向结构受力和变形的研究还不够。为了进一步完善现有研究成果的不足,本文对隧道纵向沉降原因和隧道纵向结构受力变形机制进行了研究,主要做了如下工作：(1)对各种引起隧道沉降的原因及隧道纵向变形研究情况进行了归纳整理。在此基础上,计算分析整体渗漏和局部渗漏时隧道的沉降和变形规律。(2)对运营期车辆振动荷载下隧道下卧层不排水变形和孔压消散沉降进行了计算,并将三种运营期主要引起隧道沉降的因素进行比较,得到了不同渗漏情况和地质情况时各种因素导致隧道纵向沉降的组成比例。(3)对盾构隧道管片、螺栓进行精细化建模,研究了隧道结构在纵向不均匀沉降下的受力和变形机制。计算模型考虑了环缝接头螺栓、榫头以及螺栓孔间的相互作用。分析得到了隧道接头的破坏机理,并提出基于隧道纵向沉降的隧道接头安全评估临界值。(4)对集中力作用下隧道纵向沉降变形特性进行了分析,并提出了采用调整开口环拱顶处螺栓位置和增加开口环处的加劲框等措施减小集中力作用下的接头变形和螺栓内力。更多还原

【Abstract】 The different geological setting and construction conditions will lead to the uneven longitudinal settlement of tunnel embedded in poor silty clay. And uneven longitudinal settlements will lead to over-stress the tunnel concrete segmental lining. The stress concentration will induce lining segment cracking, joint bolts yielding, joint dislocation and joint tenon crushing, which all will result in serious slurry and water leakage problems. These issues may bring great risk to metro operations and cause serious risks to the people travelling by subway. Therefore, the causes of the uneven settlement of tunnel and the failure mechanism of the tunnel lining and joints should be determined, insuring normal operations of metro, especially in deep soft soils.In recent years, the research of tunnel longitudinal settlement increases gradually. However, most of the studies focused on the tunnel settlement during construction stage, the influence on the surrounding environment, the long-term regularity of settlement and the tunnel lining design. The study of the causes of tunnel longitudinal settlement and the failure mechanisms of the tunnel is not enough.In general, some developments for tunnel longitudinal settlement are involved in this dissertation as follows:(1) The various causes of tunnel settlement and induced tunnel longitudinal deformation are summarized. On basis of these studies, the tunnel deformation and settlement during global leakage and local leakage were analyzed(2) The undrained deformation and the settlement induced by residue pore pressure dissipation under vibration load during the operation period were analyzed. Three main factors of tunnel settlement were compared and the ratios of the working factors were analyzed in different leakage conditions and geological settings.(3) To simulate the failure mechanism of tunnel segmental lining joints and longitudinal bolts under uneven longitudinal ground settlement, a numerical model with3D lining rings and bolts was established. The interactions between the lining tenons, bolts and their holes were determined. The results indicated that the deformation of the circumferential joints consisted of opening and dislocation, but the dislocation was dominant. The progressive failure of bolts and waterproofing measures were also revealed. The evaluation of structural integrity of circumferential joint and the mitigate measures were proposed in order to ensure the operational safety of a metro tunnel.(4) The deformation characteristics of tunnel lining and joints under the concentrated load were analyzed. Protection measures such as reinforced frames aroundceiling segments and a change in the location of the bolts at the crown were suggested to reduce dislocations of joints and force of bolts.更多还原