Abstract:
For all structures placed on a soil foundation, geotechnical engineers must ensure that the
soil has sufficient load carrying capacity so that the foundation does not collapse or
become unstable under any conceivable loading. The ultimate bearing capacity is the
magnitude of bearing pressure at which the supporting ground is expected to fail in shear,
i.e. a collapse will take place.
Foundation is a connecting member between the structure and the ground which supports
it or is the part of a structure that transmits the weight of the structure to the ground. All
civil engineering structures whether they are buildings, dams, etc. are built on soils. The
most conventional method of foundation design is based on the concept of bearing
capacity theories. Since the soil strata on which the foundations rest are not homogenous
always, the bearing capacity determination of foundations on layered soil system is more
significant than the homogenous soil system. Hence this research on the bearing capacity
of footing on layered soil systems (three-layered soil) plays a significant importance in
geotechnical engineering, knowing the bearing capacity of multi-layered foundations is a
key issue for coastal and offshore engineering. In this work, the effect of top layer
thickness, cohesion ratio, and soil properties of each layer on the ultimate bearing capacity
of square footing in three layered soil systems has been studied. The bearing capacity
analyzed using the numerical method has been obtained from the load-displacement curve.
There are few methods available in numerical analysis such as finite difference, finite
element method, boundary element, and discrete element. The behaviour of layered soils
can be modelled using linear to a nonlinear constitutive model which is available in the
finite element package of geotechnical application software. Among this application
software’s ABAQUS is used in the present study which is a powerful technique in
geotechnical problems to analyze complex behaviour of stress and strain due to external
loading. Nonlinear stress and strain relationship in complex geo-material of soil is easily
being predicted.