DISCHAGE CAPACITY OF HORIZONTAL DRAIN AT THE BASE OF EMBANKMENT ON SOFT SUBSOIL

Abstract

The discharge capacity (q_w) of prefabricated horizontal drain (PHD) placed at the base of embankment on soft subsoil is investigated by laboratory tests. For two PHDs tested, although their q_w values reduced with confining pressure and elapsed time, for the conditions investigated, their long-term confined in clay q_w values were more than 16, 000m³/yr/m. The field performance of PHD has been investigated by FEM analysis. Under the assumed conditions, the analysis results indicate that when q_w>1, 000m³/yr/m, q_w value will have almost no effect on embankment settlement. This suggested that the two PHDs tested are suitable as drainage material under embankment on soft subsoil