Study On Seismic Dynamic Response And Shock Absorbtion Measures Of Tunnels Through Fault

It is inevitably to pass through some of the faults in the design of mountain tunnels. First of all, the fault may increased design and construction difficulties, but ti also makes the structural force bearing conditions complicated, especially the dynamic response under an earthquake. Therefor, the problem of tunnels across fault has become a key technical issue and it is meaningful to study dynamic response of tunnels across fault broken zone.In this paper, the study on the dynamic response of tunnels across fault is contained.based on setting damping layer as the damping measure, the daping effect has been carried out on the setting of different locations and lengths.And the final work is the optimization of damping effect of foam concrete, which is the commonly used damping material.the main contents and conclusions in this thesis are concluded as follows:1. The general characteristics of dynamic response of the tunnel across fault are studied by three-dimensional numerical simulation.Consequently, the fault broken zone will increase the dynamic reponse of a tunnel within a certain range with the compares of the displacement and internal forces generated to the lining in cross-sectional and longitudinal section.2. The dampling effect has been compared under the different arrangements of the damping layer. As a result, it will increase the horizontal displacement of the secondary lining, but reduce the internal forces when the dampling layer is close to the secondary lining. So the dampling layer which is disposed between initial support and secondaryis preferably suggested as the better dampling effect.3. The dampling effect has been compared on the different lengths of dampling layer. Consequently, it is more favorable for the secondary lining when the dampling layer is disposed within a certain range of the longer length, but with increasing length, the more limited the dampling effect.4. At last, the dampling effect when using the different foam concrete are studied. Consequently, it is recommended that foam concrete with low density and elastic modulus applies to higher seismic intensity when foam concrete with high density and elastic modulus applies to lower seismic intensity.