Vacuum consolidation for construction of motor road embankments in peat soil

Abstract

One of the efficient methods to accelerate primary filtration consolidation of peat is vertical draining combined with vacuuming. This article presents the results of laboratory analysis of vacuuming impact onto the peat deformation rate in the bases of motor road embankments. It demonstrates that the duration of peat vacuuming increases and its efficiency decreases with the increase of pressure exerted by surcharge sand layer. The results of compression tests have shown that relative peat deformation after vacuum consolidation is 0.24…0.37; this means the deformation rate of the road base in the course of operation will be significantly lower. The effect of vacuum consolidation on peat settlement rate during motor road embankment construction was assessed by numerical simulation in PLAXIS software, which enables accounting for consolidation and creep processes in motor road base courses. The results of numerical simulation were used to compare the efficiency of preloading the peat using surcharge sand with the efficiency of vertical draining combined with vacuuming, considering the allowable embankment settlement rate during motor road operation. Due to a low settlement rate, the vacuum consolidation method ensures normal road operation and allows increasing the maintenance interval.