增压式真空预压处理软基的加固机理

常规的真空预压往往由于竖向排水板堵塞引起排水固结效果差、工期长。对此，笔者采用增压式真空预压处理某一站场软土地基弥补上述不足。通过分析对比增压式和常规真空预压处理方式下地基在加固期内的沉降、孔隙水压力变化特征，评价增压条件下的处理效果。结果表明：采用增压式真空预压三、四区地表沉降量明显大于常规处理的一区，且孔隙水压力消散速度也快于一区；而1.0 m间距的三区产生的预压沉降量较1.2 m间距的四区增加约30%；增压式真空预压利用增压管的增压作用能加速软基排水过程并改良排水板易淤积的不良性能。

Reinforcement of Vacuum Preloading with Air Pressure Boosted for Soft Ground Treatment

The process of drainage consolidation is usually weak and construction delivery is longer as the filling will clog the plastic drainage slab in classical vacuum preloading.Thus,a new vacuum preloading with air pressure boosted was introduced to treat soft soils of a certain railway station.To evaluate this effect of new methods,settlement and pore water pressure of the foundation are monitored and compared in the period of reinforcement.It shows that settlements in the 3rd and 4th regions where reinforcement of vacuum preloading is used are much greater than in the 1st region where normal vacuum preloading is used.Moreover,the duration time of pore pressure dissipation is shorter in above areas.The settlement of area with plastic drainage slab in space of 1.0 m is about more 30% than that in space of 1.2 m.So the mechanism of this new technique is that the boosting from ram pipe speedups drainage and overcomes the jam of mud in plastic slabs.