Abstract:
Application of vertical drains in soft clay soils is a common practice widely known to facilitate the consolidation rate. To overcome
the adverse impact of a long-lasting consolidation process, highly permeable materials such as sand and crushed aggregates are
used as drains. However, limited information exists regarding the applicability of scoria gravel as a vertical drain that no concisely
documented information is observed in the literature. Tis study hence aimed at investigating suitability of scoria as a vertical
drain in perpetuating the consolidation process of soft clay under highway embankment. Finite element-based numerical
simulation was used to model the drain. Te model was carried out by using 3D version of Plaxis software. In order to incorporate
the efect of gradual load increment on the consolidation rate, the staged construction approach was employed. Both the square
and triangular installation patterns were considered in the model in order to explore the critical efects of the drain installation
pattern on the rate of consolidation. Te numerical analysis also included varying dimensions of the vertical drain so as to
investigate the efects of the dimension parameters of the vertically installed scoria drains. Te conducted numerical analysis
revealed that the rate of consolidation was considerably accelerated with provision of a group of scoria drains. With increase in the
diameter of the drain, the consolidation rate increases, whereas the consolidation rate is inversely related to increase in drain
spacing. For the drain installed at a spacing of 2 m, a diameter of 0.4 m, and a length of 8 m any arbitrary settlement magnitude is
achieved 25 days earlier than the case without drains. Besides, incorporation of scoria drains lessens the pore pressure developed.
Te comparative analysis conducted on the efect of drain arrangement revealed that no considerable diference was witnessed in
the performance of the square and triangular installation patterns even though the consolidation rate remains slightly faster in the
case of the triangular installation pattern
