PERFORMANCE OF BAND SHAPED VERTICAL DRAIN FOR SOFT HAI PHONG CLAY

Abstract

Performance of band shaped prefabricated vertical drain (PVD) installed into soft Hai Phong clay with a 110 cm triangle arrangement is reported together with the engineering properties of the clay investigated by field and laboratory tests. Stationary piston sampling was carried out to obtain high quality undisturbed soil samples for laboratory tests and reliable engineering characteristics of the clay. It was assumed for the design of PVD spacing and preloading that the ratio of apparent value of horizontal coefficient of consolidation c_h(ap) to vertical coefficient of consolidation c_v is equal to 1.0. The settlement monitored in the field, which clearly showed that the actual settlement was faster than expected, resulted in the c_h(ap) value 1.5 times as much as c_v determined by the laboratory test.