ABSTRACT

Silty soils are fine-grained soils low strength with low hydraulic conductivity with high compressibility hence minimal bearing capacity. Foundation failure may be caused due to inadequate strength and stiffness of silty soil Buildings constructed on
silty soils may experience excessive settlement and it can reduce design life of buildings. The excessive settlement can result in cracking of the walls, roof slab and jamming of the door and windows can take place. Sometimes collapse of a building might occur. Therefore, this study proposed a method to improve the bearing capacity of the existing ground by blending granular material (by 20%, 30% and 40%
replacement) with existing soil. Three different sizes of footing (1.83x l.83 m2), (1.22x 1.22 m) and (1.22x 1.83 m2) were adopted. To calculate and bearing capacity of the shallow foundation (footings) on exiting ground, three-dimension finite
element analysis were carried out. In addition, the bearing capacity of footings on the improved ground was compared. A linear elastic perfectly plastic model with Mohr­ Coulomb failure criterion was used to capture soil behaviour. It is found that as the footing size increases, the yield point becomes higher. The percentage improvement
in ultimate bearing capacity was computed as 91%, 89% and 83% for the footing of the sizes of (l.22x l.22) m2, (l.83x l.83 m2) and (l.22x l.83 m2) founded on 40%
blended silty clay with granular material, respectively.