可液化土体中浅埋管廊上浮机制和抗浮措施研究

Study on uplift mechanism and anti-uplift measures of shallow-buried utility tunnels in liquefiable soils

为解决可液化土体中浅埋地下管廊类结构的抗浮稳定性问题。提出一种用于控制地下管廊位移的支撑抗浮装置,并通过多组振动台模型试验,验证LS型支撑抗浮装置在地基土液化条件下的工作性能,探明钢板桩间距和斜拉板倾角对支撑抗浮装置工作性能的影响规律,揭示支撑抗浮装置在地基土体液化条件下的抗浮机制。研究结果表明:地基土液化过程中廊底动土压力逐渐增大、廊顶动土压力迅速减小是廊体失稳上浮的原因。LS型地下管廊支撑抗浮装置可有效控制地基土液化导致的管廊上浮问题,并降低廊体应变响应;采用L=150 mm的拉森钢板桩间距及斜拉板倾角为α=45°的支撑抗浮构件时管廊结构受力及变形较小。结论可为地下管廊抗浮稳定性问题提供一定的参考依据。

To solve the problem of anti-floating stability of shallow buried underground utility tunnel structures in liquefiable soil,a support and anti-floating device designed to control the displacement of underground utility corridors is introduced.Through multiple sets of shaking table model tests,the operational performance of the LS-type support and anti-floating device under liquefied soil conditions is validated.Additionally,the impact of the spacing between steel sheet piles and the inclination angle of diagonal bracing plates on the performance of the support and anti-floating device is investigated.Furthermore,the anti-floating mechanism of the support and anti-floating device under liquefied soil conditions is elucidated.The results indicate that during the process of soil liquefaction in the foundation,the soil pressure on the bottom of the corridor gradually increases,while the soil pressure on the top of the corridor rapidly decreases,leading to the instability and uplift of the corridor.The LS-type underground utility corridor support and anti-floating device effectively mitigates the uplift problem caused by soil liquefaction in the foundation and reduces the strain response of the corridor.When using a spacing L=150 mm between Larson steel sheet piles and an inclination angle of diagonal bracing plates ofa=45°,the structural forces and deformations of the utility corridor are relatively small.The conclusion can provide reference basis for the anti-floating stability of underground utility tunnel.