Research on Horizontal Coefficient of Consolidation of Vietnam’s Soft Soil

Abstract

The horizontal coefficient of consolidation is the most important parameter for designing the improvement of soil soft by prefabricated vertical drains (PVDs) combined with surcharge and vacuum preloading. This paper presents the experimental study on the horizontal coefficient of consolidation (ch) of some soft soils distributed in Vietnam. Thechvalue was determined by the laboratory test and CPTu dissipation test. The laboratory tests included the Rowe consolidation cell test and constant rate of strain consolidation with radial drainage test. Two types of consolidation laboratory tests were performed. The experimental results indicated that thechvalue is always larger than the vertical coefficient of consolidation of soil (cv). The ratio ofch/cvdepends on the consolidated pressure, type of soil, and the anisotropy of soil. The ratio ofch/cvis different in different types of soft soil in Vietnam. In the normally consolidated state, thech/cvratio ranges from 1.35 to 10.59. It was necessary to choose thechvalue at the consolidated stress level for calculating the PVD spacing.