Abstract: Based on Barron’s equal strain consolidation theory, the consolidation governing equation of sand-drained ground under vacuum combined surcharge preloading is derived, and a general analytical solution is obtained, which considers the vacuum loading process, the time-dependent surcharge loading, the characteristics of the vacuum pressure decreasing along with the depth and radial direction, and the smear effect of vertical drains and the vertical flow. The correctness of the analytical solution proposed in this paper is verified by comparing the degenerate analytical solution with the existing analytical solution and the finite difference solution. Based on the analytical solution, the consolidation behaviors of sand-drained foundation are analyzed. The results show that the consolidation rate of sand-drained ground is accelerated with the increase of vacuum loading factor η. However, when η increases to a certain extent, the influence of the vacuum loading process on the consolidation rate of sand-drained ground can be ignored. The consolidation rate of sand-drained ground decreases with the increase of vacuum pressure attenuation coefficients k1 and k2. The consolidation rate of sand-drained ground decreases with the increase of vacuum pressure p0 and increases with the increase of final surcharge loading qu. With the increase of loading time Th1, the consolidation rate of sand-drained ground decreases gradually, and the consolidation rate is the largest under instantaneous surcharge loading.

Key words: vacuum loading process, surcharge loading, vacuum combined surcharge preloading, sand-drained ground, general analytical solution