Soil liquefaction induced manhole uplift causes significant disruptions to vital lifelines following major earthquakes. In the past decades, remediation measures have been proposed to tackle this problem for newly constructed manholes. Nonetheless, mitigation measures for existing manholes were rarely reported, which leaves existing manholes facing high uplift risk in future earthquakes. Aiming to address this problem, this study proposes a series of mitigation measures, including (1) opening a drainage hole at the manhole base, (2) installing a smooth permeable pile under the manhole, and (3) installing a permeable pile with spiral wings under the manhole. The experimental results revealed that these three methods can mitigate manholes uplift to different extents. The drainage opening can mitigate the manhole uplift by releasing the pore water pressure on the manhole invert and draining water into the manhole chamber. The smooth permeable pile can further mitigate the manhole uplift with more drained water and greater retained sidewall friction due to the lowered liquefaction degree in the surrounding soil as a result of the extended drainage effect. However, the additional pull-out resistance expected from the spiral wings was of little contribution in view of the slight uplift difference comparing to the smooth permeable pile. The above observations are also validated with theoretical force equilibrium.

发生大地震后，土壤液化引起的沙井抬升对生命线造成重大破坏。在过去的几十年中，已经提出了补救措施来解决新建的人孔的问题。然而，鲜有关于缓解现有沙井的措施的报道，这使现有沙井在未来的地震中面临着高抬升风险。为了解决这个问题，本研究提出了一系列缓解措施，包括（1）在人孔底部打开排水孔；（2）在人孔下方安装光滑的可渗透桩；（3）安装螺旋形的可渗透桩。沙井下的翅膀。实验结果表明，这三种方法可以不同程度地减轻人孔的抬升。排水孔可通过释放井盖倒置孔上的孔隙水压力并将水排入井盖室来减轻井盖的隆起。光滑的可渗透桩由于排水作用延长而导致周围土壤液化程度降低，因此排水更多，残留侧壁摩擦更大，可以进一步减轻人孔的隆起。但是，与光滑的可渗透桩相比，由于轻微的隆起差异，螺旋桨翼预期产生的附加抗拔阻力几乎没有贡献。上述观察结果也得到了理论力平衡的验证。光滑的可渗透桩由于排水作用延长而导致周围土壤液化程度降低，因此排水量更大且残留的侧壁摩擦力更大，可以进一步减轻人孔的抬升。但是，与光滑的可渗透桩相比，由于轻微的隆起差异，螺旋桨翼预期产生的附加抗拔阻力几乎没有贡献。上述观察结果也得到了理论力平衡的验证。光滑的可渗透桩由于排水作用延长而导致周围土壤液化程度降低，因此排水量更大且残留的侧壁摩擦力更大，可以进一步减轻人孔的抬升。但是，与光滑的可渗透桩相比，由于轻微的隆起差异，螺旋桨翼预期产生的附加抗拔阻力几乎没有贡献。上述观察结果也得到了理论力平衡的验证。