Research on the dynamic responses of shallow-buried depth tunnel under the Action of Rayleigh waves

摘要

It has been proved by the seismologic observation of 5.12 Wenchuan Earthquake that a large number of shallow-buried depth mountain tunnels at the portal are underwent severe damage. Earthquake waves, especially Rayleigh waves may be a major factor causing the damage. The numerical model of the shallow-buried depth mountain tunnels by FLAC3D is establishes in this paper, and the dynamic responses of the shallow-buried depth mountain tunnels under the action of Rayleigh waves are simulated by loading on normal Rayleigh waves. The effect of different strength of surface waves is simulated by the in-site blasting tests. The dynamic responses of the tunnel lining under the action of Rayleigh waves are obtained by filtering and composition separation in order to discuss the incidence and mechanism of action. The results show that the dynamic responses of tunnel lining under the action of Rayleigh waves mainly focuses on the portal of tunnel, namely the buried depth and lengthways depth of the tunnel are 0～16m and 0～20m, the tunnel lining is damaged easily in the incidence, and the multiplicative effect of Rayleigh waves often occurs at the portal;;beyond the incidence, Rayleigh waves attenuate rapidly and the dynamic responses of the tunnel lining decreases gradually, which has little effects on the safety of tunnel structures.