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