Influence of Aspect Ratio on the Bearing Capacity and Correlated Modulus of Subgrade Reaction for Shallow Foundations on Dense Sand
Abstract
One of the most fundamental problems in the field of geotechnical engineering is the
prediction of bearing capacity and settlement of shallow foundations on cohesion-less
soil subjected to vertical central loading. The fact is that commonly used "SHAPE
FACTORS" in the current design practice for estimating the bearing capacity and
modulus of subgrade reaction of a shallow foundation are partially empirical values
proposed by (Terzaghi, 1943). On the other hand, the current design of shallow foundation
on cohesionless soil does not take into consideration the scale effect between the soil
particles and foundation geometry. This may result in an excessively conservative design,
which in turn results in unnecessary costs of the foundation. Therefore, and to take into
account the realistic effect of the three-dimensional mechanism of soil deformation for
foundations with various aspect ratios B/L on the shape factor in the classical formulas
and theories of ultimate bearing capacity of shallow foundation, a series of small-scale
model foundation tests were carried out on a practical type of sand (Toyoura sand)
and the three-dimensional mechanism of deformation has been closely monitored and
recorded at the end of each performed test. This research presents the main observations
and results of the square, rectangular and strip model tests with constant foundation base
width B conducted on compacted sand. Finally, the results are presented and compared
to those from literature and preliminary conclusions and recommendations are drawn.