Study On Seismic Dynamic Response Of Tunnel Stimulated By Traveling Wave In Highlyseismicregion

With the development at full speed of economic construction of our country, large numbers of tunnels for highway, railway, and water and electricity projects have been constructing. Seismic performance of the tunnel structure is given greater attention after the heavy earthquake of 5.12 Wenchuan.The research on dynamic response of the tunnel based on the uniform excitation has obtained some achievements at present, but the research based on wave excitation is still not enough. Longitudinal anti-seismic fortified length at tunnel portal is just given a limit value in practical projects. Apparently, there is a certain one-sidedness of such a provision.In response to these problems, we firstly survey the earthquake damage of tunnels at home and abroad, and then summarize the characteristics and laws of earthquake damage of tunnels, finally analyse the dynamic response of the tunnel and longitudinal anti-seismic fortified length at tunnel portal together. The paper acquires a breakthrough that the tunnel dynamic response is mainly based on the uniform excitation, researchs on factors affecting traveling wave effect, analyses the relationship between longitudinal anti-seismic fortified length at tunnel portal and span of tunnel, and brings forward a concept of multi-segment and multi-defence system of earthquake.In this paper, the main studies in the following are:1. Summarize the earthquake damage formal, impact factors and failure mechanism of tunnel;2. Studies on dynamic response theory of tunnel such as traveling wave effect,soilstructure interaction,soil dynamic constitutive relation and rock safety assessment methods.3. Studies on numerical simulation conditions such as boundary condition,input power motivation theory,damping model and spread and baseline correction of seismic wave.4. Comparative analysis of dynamic response of the tunnel beween traveling-wave stimulation and uniform excitation.5. Analysis of the factors of travling wave effect such as seismic wave,apparent wave velocity,tunnel structure and rock level.6. Research on longitudinal anti-seismic fortified length at tunnel portal, analysis of the relationship between longitudinal anti-seismic fortified length at tunnel portal and span of tunnel, and brings forward a concept of multi-segment and multi-defence system of earthquake.Through the above studies, not only dynamic response characteristics based on traveling-wave stimulation of tunnel are analyzed in depth, but also earthquake resistant design technology at tunnel portal are further advanced.