【作者】 洪开荣；

【导师】 王梦恕；

【作者基本信息】 北京交通大学 ， 桥梁与隧道工程， 2011， 博士

【摘要】 摘要：从环保要求与可持续发展战略考虑,水下隧道必将是我国跨江越海交通工程的主要选择方式。广深港高速铁路狮子洋隧道作为我国首座特长水下铁路隧道,设计速度达350km/h,也是我国首次采用盾构对接方法施工的水下隧道,其建设理念与方法对今后我国跨江越海工程的建设具有很大的借鉴作用,因此研究狮子洋水下盾构隧道的修建技术,不仅具有重要理论意义,而且具有重要的社会经济意义。本论文以广深港高速铁路狮子洋隧道工程为依托,对高速铁路水下盾构隧道结构力学特征及掘进与对接技术进行了深入的研究。主要研究内容和成果如下：(1)对盾构管片结构设计方法进行了较系统的研究。首先总结了传统管片设计结构模型对各项设计参数的取值,分析其不足之处；之后,确定采用修正后的梁-接头模型作为管片结构设计方法,进行了数值模拟计算,并通过大量的原位测试,验证了管片结构接缝和管片均处于受压状态,提出了管片结构的荷载折减与提高隧道经济性的设计措施等观念。(2)由于管片隧道为拼装式结构,拼装式管片在其周边介质的发生变化时会成为外扩式不稳定结构,极易导致隧道的失稳。通过采用修正的梁-接头模型方法,分析了拼装式管片衬砌的可能破坏特征,论证了水下盾构隧道增加二次衬砌确保隧道结构稳定,提出了设置二次衬砌的必要性。(3)在狮子洋隧道施工中,通过大量监测数据,并对由隧道施工引起的地表沉降进行分析,得出隧道纵向、横向地表沉降规律；分析了隧道施工各种地层土体的水平位移,总结了其相应的水平位移规律。同时得出了盾构隧道本体除了出现整体上浮外,几乎没有相对位移、地表隆沉与隧道本体结构变形无直接关系的结论,因此建议今后对盾构隧道可不必进行隧道本体变形监控量测。(4)针对狮子洋隧道横向与纵向均存在软硬不均问题所带来的盾构掘进与控制的技术难度,通过对岩土层磨蚀性与岩土成份试验,对刀具的金相和磨损规律进行了研究,提出了有效的刀具磨损规律方程。通过对0.67MPa高水压下刀具更换技术的研究,提出了减压限排换刀技术,并根据不同地段盾构刀具的掘进效果评价,对狮子洋隧道盾构刀具进行设计与改进。(5)根据现场不断变化进度情况,详细研究了多处狮子洋隧道对接点的工程地质及水文地质,并相应对接点的贯通精度进行了估算,确定了合理的隧道洞内控制测量精度；利用离心试验和数值模拟分析,确定满足对接处的隧道稳定的预留对接宽度不应小于2.5m,但在保压状态下对接宽度在0.5m是也是安全的。实际施工时,采用了在两台盾构相距20～30m时,一台盾构停止掘进并保压,另一台盾构向前掘进无限对接,然后在盾壳的保护下,拆除盾壳内部构件,并将两刀盘外圈梁焊接联通隧道,再施工钢筋混凝土衬砌的施工方法,达到了安全、精确、高效的对接目标(平面误差小于30mm、水平误差小于20mm),为水下盾构隧道相向掘进对接提供了宝贵经验。本文就广深港高速铁路狮子洋隧道的主要修建技术进行研究与分析,期望其成果对我国将来的跨海隧道建设提供参考与借鉴。更多还原

【Abstract】 Abstract:For the sake of environment protection and sustainable development, underwater tunnels must be the favorable solution for transportation corridors to cross seas and rivers in China. Shiziyang tunnel on Guangzhou-Shenzhen-Hong Kong high speed railway is the first underwater super-long railway tunnel in China. The designed train-running speed of the tunnel is 350km/h. Shiziyang tunnel is also the first underwater tunnel in China that has been constructed by shield-docking method. The construction concept and methods of Shiziyang have great reference significance for the construction of future tunnels crossing seas and rivers in China. Therefore, the study on Shiziyang tunnel does not only have great theory significance, but also have great social and economic significance.In this dissertation, the structural and mechanical performance of underwater shield-bored high speed railway tunnels and the boring and docking technologies are studied in detail, with Shiziyang tunnel on Guangzhou-Shenzhen-Hong Kong railway as an example. The major contents and achievements of the study are as follows:(1) The methods for the design of the segment structures are studied systematically. First, the values of the design parameters in the conventional segment structure design models are summarized and the disadvantages are analyzed; secondly, modified beam-joint models are determined to be adopted as the segment structure design method, numerical simulation calculations are made, the structural joints of the segments and the segments themselves are verified, by means of numerous in-situ tests, to be under compressing state, and concepts such as the reduction of the loads on the segment structures and the design countermeasures to improve the economical efficiency of the tunnel are proposed.(2)Tunnels with segment lining have an assembled structure. In case any changes occur to the resistance of the media surrounding the assembled segments, the assembled structure is liable to become an instable outward-expanding structure, which may cause the tunnel to lose its stability. By means of modified beam-joint model method, the potential failure properties of the assembled segment lining are analyzed, the solution to install the secondary lining for underwater shield-bored tunnels so as to ensure the stability of the tunnel structures are expounded and the necessity to install the secondary lining is presented. (3) The ground surface settlement induced in the construction of Shiziyang tunnel is analyzed and the rules of the ground surface settlement in the longitudinal and transverse directions are obtained as a result of numerous monitoring data; the horizontal displacement of various strata in the course of the tunnel construction is analyzed and the corresponding horizontal displacement rules are summarized. Furthermore, conclusion is drawn that except for the overall lifting of the shield-bored tunnel, almost no relative displacement occurs to the tunnel and that there are no direct relations between the ground surface heaving/settlement and the tunnel structure deformation. Therefore, it is recommended that it is unnecessary to monitor the deformation of the shield-bored tunnel structure itself in the future.(4) The geological conditions of Shiziyang tunnel are heterogeneous both in transverse direction and in longitudinal direction, which imposes great technological difficulty for the boring and control of the shield. The metal phase and wearing rules of the cutting tools are studied by means of tests on the strata abrasiveness and strata compositions and effective cutting tool wearing rule equations are proposed. The technology to replace the cutting tools under 0.67MPa water pressure is studied, the cutting tool replacement technology under reduced pressure and limited slurry releasing is proposed, and design optimizations are made to the cutting tools of the shield for Shiziyang tunnel on basis of the assessment on the boring effect of the shield in different tunnel sections.(5) The engineering geological conditions and hydro-geological conditions of the potential shield docking positions of Shiziyang tunnel are studied in detail. Appropriate inside-tunnel control survey accuracy is determined by estimating the influence of the docking position on the break-through accuracy. It is determined, by means of centrifugal tests and numerical simulation analysis, that the preserved docking width that can ensure the stability of the tunnel at the docking position shall not be less than 2.5m, however, under the pressure-maintaining condition,0.5m docking width can also ensure the safety. In the tunneling, the docking is made as follows:When the distance between the two shields is 20-30m, one of the shield stops its boring while maintaining the pressure in its excavation chamber, the other shield continues its boring to dock with the shield that has stopped its boring. Under the protection of the shield shell, the components within the scope of the shield shell are dismantled, the outer rings of the cutter heads of the two shields are welded together to form the tunnel structure, which is followed by the installation of the reinforced concrete lining. In this way, safe, accurate and efficient docking has been accomplished, with the plan error being less than 30mm and the horizontal error being less than 20mm. The successful docking of the shields in Shiziyang tunnel provides valuable experience for the docking of shields in boring of other underwater tunnels in the future.The major construction technologies adopted for Shiziyang tunnel on Guangzhou-Shenzhen-Hong Kong high speed railway are studied and analyzed in the dissertation, with the hope that the study results can provide reference for the construction of sea-crossing tunnels to be built in China in the future.更多还原