双排圆桩加固下隧道斜穿滑坡体系的动力响应特征研究OA

[Objective]To investigate the deformation mechanisms and damage characteristics of a tunnel reinforced with double-row circular piles obliquely crossing a landslide under seismic conditions,[Methods]a shaking table model test was conducted using the Guojiapo tunnel landslide project in Gansu Province as the prototype.The landslide mechanism was clarified based on the deformation characteristics.Energy identification methods using the Hilbert spectrum and marginal spectrum were adopted to identify tunnel damage,and the peak Fourier spectrum amplitude(PFSA)was used to verify the accuracy of the proposed method.[Results]The results showed that the slope deformation process included seismic-induced trailing-edge settlement,mid-slope shear,slope-toe traction,and overall sliding.The presence of double-row circular piles inhibited the rapid overall sliding of the slope,and landslide thrust was transmitted along the anti-slide piles,resulting in the formation of the main sliding zone.The superposition of seismic wave reflection and refraction produced a significant acceleration amplification effect in the lower part of the slope,causing rapid deformation and failure in the lower slope and subsequently dragging the middle and upper parts into deformation and failure.Stress was transmitted along the anti-slide piles to the right side,resulting in stress concentration and more severe damage in the lower right part of the slope.f2(26～36 Hz)primarily induced the overall dynamic response of the tunnel,whereas f3(47～53 Hz)mainly induced the local dynamic response.The double-row circular piles reduced the dynamic response of the right-line tunnel.The multi-peak phenomenon of peak seismic Hilbert energy amplitude(PSHEA)indicated the occurrence of damage,and the damage trend of the right-line tunnel reflected the overall deformation and failure process of the slope.The variation trend of peak marginal spectrum amplitude(PMSA)was consistent with that of PSHEA,confirming that the most severe damage occurred at the riverside arch waist of the right-line tunnel,followed by the inverted arch.PSHEA(25～40 Hz)and PMSA(15～30 Hz)proved that f2 induced the overall deformation and failure of the right-line tunnel.The multi-peak phenomenon of PSHEA could be used to identify locations of energy loss,while PMSA distribution clearly reflected the energy transfer and overall damage of the tunnel.Using both methods revealed the damage characteristics and spatial dynamic response of the tunnel.[Conclusion]The research findings are of great significance for studying the dynamic response and failure mode of tunnel systems obliquely crossing landslides under seismic conditions.