The Behaviour of Confined Granular soil loaded by a square footing

Dhiaadin Bahaadin Noori Zangana

Civil Engineering Department, Faculty of Engineering, University of Sulaimani – Kurdistan Region

This research involves the behaviour of confined granular soil supported by a
square footing. A series of bearing capacity tests were carried out on a small-scale
laboratory model, which filled with sand, placed in a dense state and confined with
UPVC cell. The response of an unconfined state was measured in the beginning,
and then compared with the confined sand. The studied variables included the
cylinder height and diameter, the depth of the footing to the top of the cylinder and
the embedded depth of the footing.
The test results indicated that the soil confinement resists lateral displacement of
sand underneath the footing, which is leading to a significant improvement for the
response of the footing. The curves of load-settlement generally showed the same
trend in all the cases. Failure was considered as a settlement, which was equal to
8% of the total footing width. Also, the recommended optimum cell height,
diameter, footing depth to the top of the cylinder and the embedded depth of
footing that give the maximum bearing capacity improvement were presented and
discussed. According to the present research results, a conclusion based on the soil
confinement role and found to be notably increased the bearing capacity and
stiffness. Furthermore, a modification of load–settlement behaviour of the sub
grade sand was also gained.

Key Words: Square Footing, Bearing Capacity, Load-Settlement Behaviour, Granular Soil, Confinement 


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