Seepage Analysis for Vacuum-Surcharge Preloading Method

Based on Barron's co vertical formulas, a seepage model for the vacuum surcharge preloading method is developed, and a seepage equation and its analytical solution are given. In combination with the characteristics of subgrade construction in stages, a formula is deduced for calculation of seepage under the condition of loading in stages. With the formula, the number of vacuum pumps needed is checked, and the decrease of groundwater table and variation of seepage water pressure with depth are calculated, providing a basis for further decrease of electric power consumption in vacuum pumping. An example shows that the calculated result is in good agreement with the measured result.