Abstract:
Construction of road embankments over soft soil such as expansive clay is so tiresome that the
consolidation process may continue for a long time. This typical feature of the clay soil is associ ated with its poor potential to dissipate excess pore pressure when subjected to construction load..
The current study hence aimed at investigating the potential performance of vertically installed
scoria drains in perpetuating consolidation process of the clay inhabited ground so that the com pressible ground. A finite element method was used to model the soft clay reinforced with a group
of scoria drains. Three dimensional version of Plaxis software utilized to simulate both the pore
water and deformation attributes of the problematic clay soil under embankment load. Likewise,
both hardening soil and soft soil constitutive models were adopted to model the material proper ties. To systematically explore the critical effects of drain installation patterns, both square and
triangular patterns were employed so that comparative analysis on effectiveness of the two meth ods in speeding up rate of consolidation could possibly be conducted. Besides, parametric study
so as to assess influence of diameter, length and spacing of the drain was conducted. Finding of
the study revealed that using scoria drain significantly improved consolidation rate of the clay
soil. For any arbitrary time duration, considerably larger magnitude of vertical deformation was
observed when using triangular installation pattern than that of square pattern. Besides, it was
indicated that when using 8m, 12m and 15m long drains, the consolidation time was lessened by
35-79%, 44-86% and 54-89 % respectively. The rate of water dissipation increased with area
replacement ratio which is directly related to drain diameter and spacing. The study apparently
demonstrated that variation in magnitude of the dimension parameters significantly resulted in
abrupt change in defamation performance of the clay soil
