厦门海底隧道海域风化槽段围岩稳定性研究

STUDY ON STABILITIES OF SURROUNDING ROCKS THROUGH WEATHERED SLOT IN XIAMEN SUBSEA TUNNEL

厦门东通道海底隧道是一项规模宏大的跨海工程,是连接厦门市本岛和翔安区陆地的重要通道,也是中国大陆第一座采用钻爆法修建的大断面水底隧道,工程于2007年下半年由陆域进入施工难度最大、最危险的海域部分,其中的海底风化槽地段采用CRD工法进行施工,隧道开挖、支护过程中围岩和支护结构的受力和变形特征广为人们所关注,因此对于该段隧道稳定性的研究具有重要意义。应用大型有限元软件ABAQUS,依据流固耦合理论,对翔安隧道风化槽段隧道CRD工法的施工过程进行了三维动态仿真数值模拟,研究隧道施工过程中围岩的应力场、位移场、外水压力分布规律以及支护结构受力情况和衬砌外水压力的分布规律,研究成果为该隧道施工和同类工程建设提供了理论依据和实践经验。

East passageway of Xiamen subsea tunnel is a huge sea-crossing project. It is a significant route connecting Xiamen island with Xiang＇an city. Furthermore, it is the first large cross-section subsea tunnel in China, which is constructed with drill and blasting method. The construction will go through the most unfavorable strata and the most difficult construction was found in the latter half year of 2007. The CRD method is used to excavate the weathered slot. The mechanical behaviors and deformational characteristics of the supporting structures and host rock during the tunnel excavation are highly focused on recently. From the characteristics of the excavation, based on the hydro-mechanical coupling theory, the CRD construction process in the weathered slot is simulated with finite element software ABAQUS. The distributions of stresses, external water pressures and displacements in the host rock, the distributions of stresses in the supporting structures, the external water pressures of initial lining during the CRD construction process are analyzed. The obtained results from the research work are useful for the tunnel construction, and it will provide references to other projects in practice.