间歇式PHD-PVD真空预压处理疏浚淤泥地基试验研究

    Experimental study on intermittent PHD-PVD vacuum preloading treatment of dredged slurry foundations

    • 摘要: 针对PHD-PVD(水平联合竖直排水板)真空预压处理疏浚淤泥地基时,排水板淤堵严重造成土体固结效果不佳的问题,采用间歇式抽真空的方法以进行改善,即间歇式PHD-PVD真空预压法。试验设计了五组室内模型试验与现场试验,监测疏浚淤泥加固过程中的排水量、孔隙水压力、表层沉降以及试验后土体的含水率和抗剪强度,研究间歇式真空预压对疏浚淤泥加固效果的影响。试验结果表明:间歇式PHD-PVD真空预压显著提高了疏浚淤泥加固效果。相较于传统PHD-PVD真空预压组,间歇式PHD-PVD真空预压试验组排水量提高14.69%,沉降量增大13.94%,十字板剪切强度提升21.30%,表明间歇式PHD-PVD真空预压法对排水板淤堵进行了有效缓解,从而提高了固结效率。为验证该方法处理实际疏浚淤泥地基的可行性,进行了真空预压现场试验,结果证实该方法具有显著的加固效果,为今后类似工程提供一定的设计指导。

       

      Abstract: To address the issue of severe drainage plate clogging during the treatment of dredged slurry foundations using PHD-PVD (horizontal combined with vertical drainage plate) vacuum preloading, which leads to inadequate soil consolidation, the intermittent vacuum preloading method was adopted for improvement. This approach is referred to as PHD-PVD vacuum preloading combined with the intermittent method. The experimental program comprised five sets of laboratory model tests and a field test. Parameters including drainage volume, pore water pressure, and surface settlement were monitored during the reinforcement process of the dredged slurry, while the soil moisture content and shear strength were measured after testing. This was conducted to investigate the influence of intermittent vacuum preloading on the reinforcing effect of the dredged slurry.The experimental results show that, the intermittent PHD-PVD vacuum preloading significantly enhanced the reinforcing effect of dredged slurry foundations. Compared with the conventional PHD-PVD vacuum preloading, the intermittent PHD-PVD vacuum preloading group increased the drainage volume of dredged slurry by 14.69%, the settlement increased by 13.94%, and the vane shear strength increased by 21.30%. It indicates that the intermittent PHD-PVD vacuum preloading method effectively reduced the clogging near the drain, and the consolidation efficiency was improved. To verify the feasibility of this method for treating actual dredged slurry foundations, a field vacuum preloading test was conducted. The results confirmed that the method provides a significant reinforcing effect, offering valuable design guidance for similar projects in the future.

       

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