Analysis of Bearing Capacity of Strip Foundation on Cohesive Soil with Soil Patch of Different Property Using FEM

Abstract

ABSTRACT Soil in its natural form is a non-homogeneous mass, with possibilities of consisting more than one layer and pockets of heterogeneity. The pocket of heterogeneity explicitly includes the presence of void and the presence of soil of contrasting properties. Such pockets or patches of discontinuity in the soil may cause unfavorable and unpredictable performance of the foundation build over them. In that case, such pockets of soil should be studied thoroughly before construction over or near its vicinity. The present study deals with the determination of bearing capacity of surface strip foundation resting over cohesive soil with continuous square soil patch of different consistency than that of parent soil. The analysis was made using the finite element software in which the soil was modelled as an elastic perfectly plastic material. The soil domain was discretized using 15-noded plane strain triangular elements. The parametric study includes the effect of vertical and horizontal position of square shaped soil patch with respect to foundation, effect of size of the soil patch and effect strength characteristics of soil patch on the bearing capacity and deformation behavior of the soil beneath the surface strip foundation. The results of the study indicates that there is a critical zone of influence underthe foundation. The performance of thefoundation will be significantly influenced dueto existence of the soil patch in the parent soil layer only when it is located within thisregion. The size of this zone of influencedepends on various factors as soil property ofthe parent soil and soil patch and the size of thefoundation and soil patch.When the soil patch is located within the critical zone, the bearing capacity of the foundation varies considerably with the location of the soil patch. It is also observed that, severity of the effect of soil patch on the performance of the foundation is directly proportional to the size of the soil patch and inversely proportional to the strength of the patch soil.