Cause Analysis And Countermeasure Study On The Abnormal Deformation Of Xia'men East Passage Subsea Tunnel

Since Xia'men east passage subsea tunnel has been constructed, dangerous case has happened many times in the subsea tunnel. Field monitoring measurement shows that a lot of tunnel cross section's crown settlement and level convergence exceed design requirement and criterion. Based on field monitoring measurement data, the thesis summarizes the cause and countermeasure for abnormal deformation of each kind and offers some beneficial conclusions and suggestions to the subsea tunnel construction.This paper mainly consists of three parts, which are abnormal deformation classification, cause analysis for abnormal deformation of each kind and countermeasure study on abnormal deformation of each kind.Focusing on Xia'men east passage subsea tunnel, the paper analyzes field monitoring measurement data in detail. According to criterion and reference research, the abnormal deformation is classified into three categories: crown settlement abnormity, level convergence abnormity and abnormal deformation of temporary support. Combined with experiment for mechanics parameters of surrounding rock, monitoring measurement data and numerical calculation, the paper analyzes the cause for abnormal deformation in the aspect of geological condition, cross section closed distance and time, integral sinking, sequence of CRD method excavation. Sequentially, the main cause for abnormal deformation of each kind is respectively fixed out.It has taken various measures against abnormal deformation, including enhancing stiffness and intensity of temporary support, setting locking anchor bar, grouting in inverted arch, constructing continuous wall for drawdown and so on. According to numerical calculation and monitoring measurement data, each measure's effect of function and application is researched. Finally, the countermeasure for abnormal deformation of each kind is offered.