DYNAMIC RESPONSES OF DOUBLE MOUNTAIN TUNNELS UNDER SV WAVES

According to the theory of elastic fluctuation and combined with the area-partition and region-matching techniques, we adopted a high precision indirect boundary element method to investigate the seismic response characteristics and the interaction of a tunnel-mountain system under an SV wave incidence. Through a parametric analysis, we investigated the influence of the frequency, incident angle and lining tunnel location on the nearby ground movement and the stress and displacement in the lining tunnel. The lining tunnels in the mountain had a significant amplification effect on the nearby seismic wave. With the increase in the dimensionless frequency η, the circumferential stress of the tunnel decreases, the surface displacement oscillated more intensely and the spatial distribution became more complicated. When the size ratio of the mountain to the tunnel was small, the circumferential stress concentration in the tunnel was obvious. With the increase in the size ratio, the circumferential stress decreased and stress concentration area was significantly reduced. With the increase in the incident angle α of the SV wave, the circumferential stress in the lining was increased. In addition, the concentration effect was more significant for the dynamic stress of the lining when space between the tunnels was small.