| Bored cast-in-place concrete piles founded in McMurray Formation oil sand (oil sand) have been used to support heavily loaded structures at a majority of the extraction and upgrading plant sites in the Fort McMurray, Alberta area since the early 1970's. Traditionally, these structures have been founded on expanded base (belled) piles, which primarily rely upon end bearing resistance to carry the loads. Of recent, a series of field scale pile load tests have been completed for new facilities where very high shaft resistances in the oil sand have been measured. Because of this, straight shaft cast-in-place concrete piles designed using shaft resistance have effectively eliminated the need for expanded bases.;Recent case studies from multiple load test sites in oil sand are examined where the mobilized shaft resistances and axial load capacities are compared. A literature review has been completed to study the constitutive behaviour of oil sand. The current state of practice in design of statically loaded cast-in-place concrete piles and geotechnical behaviour is reviewed. Finally, a numerical analysis via finite element method is used to model a field scale pile load test. This model, capable of capturing shear dilation and elastic-plastic deformations, provides a complete set of stresses and strains which demonstrate increases in radial stresses due to shear dilation. With these results, areas of further study are recommended.;Oil sand in its natural state exhibits a characteristic interpenetrative granular fabric with surface rugosity and grain interlocking. High dilatancy, high shear strengths and reduced porosities are material properties unique to oil sand. This thesis postulates that high shaft resistances in oil sand are primarily a function of shear dilation. The plastic volumetric expansion caused by shearing is constrained, resulting in an increase in horizontal/radial stresses between the pile and soil interface, effectively increasing shearing resistance. |
