Study On Construction Disturbance Impact Of Expressway Multi-arch Tunnel

Since the beginning of this century,Chinese expressway construction hasdeveloped rapidly and multi-arch tunnel is widely used in expressway as a new typeof structure. Even though the application,there are a lot of investigative content of themulti-arch tunnel in design and construction based on expressway, as it is developedrelied on the method of engineering analogy. Therefore,it can provide technicalsupport for the safe construction of multi-arch tunnel to analyze the adaptability ofExpressway multi-arch tunnel and disturbance influence which the multi-arch tunnelmakes to surrounding rock.The thesis discusses the scope of application of multi-arch in Expressway,andcompares multi-arch tunnel with separated tunnel and neighborhood tunnel based onDuimenpo multi-arch tunnel of Fenghuang to Daxing highway in Hunan province.Then establishes standard and Duimenpo models by finite element analysis softwareMIDAS/GTS, analyzes the variation law of surrounding rock's displacement andstress field affected by construction disturbance. Finally validates the viability andreliability of numerical simulation results by comparing the actual field monitoringdata.The author gets the conclusion that the multi-arch tunnel is more suitable for thehighway which hold the conditions such as short distance and strict environmentalprotection by comparing the differences in application conditions and constructioncost among multi-arch tunnel, separated tunnel and neighborhood tunnel. Afteranalyzing the simulation results of step methods in level Ⅳ surrounding rockbetween the standard model and Duimenpo tunnel model, the author finds that boththe two models have common characteristics in displacement and stress fieldsinfluenced by the same construction process,and they better indicate the variation lawof disturbance of surrounding rock affected by multi-arch tunnel construction. What'smore, the author validates the reliability of numerical simulation results by comparingthe actual field monitoring data of Duimenpo multi-arch tunnel with the result ofnumerical analysis, and indicates that results of vault subsidence, horizontalconvergence and surrounding rock pressure simulated by MIDAS/GTS finite elementare consistent with the actual monitoring results.The results of this thesis can not only provide theoretical support for the choiceof expressway multi-arch tunnels design, but also provide certain reference for the safety of construction quality in multiple-arch tunnel.