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Abstract To study the effect of particle shape on mechanical and deformation properties of sand，three kinds of sands with different particle shapes and similar materials that are glass beads are selected. A light microscope is employed to capture the particle digital images，which are then processed to obtain the geometric parameters of particles. Two shape parameters，sphericity and roundness，are defined and quantified using the plug-in JAVA language. A series of direct shear and centrifugal cone penetration tests(CPTs) are conducted to examine the relative effect of particle shapes on the shearing friction angle and pile tip resistance. The direct shear test results show that the critical friction angle reduces linearly with the increase in roundness and particle regularity，while the dilation angle increases with the increase in particle irregularity. A modified equation can be employed to describe the relative effect of particle shapes on the peak friction angle. The centrifugal tests indicate the CPTs can be highly relied upon in the case of predicting the pile tip resistance. The sand that has a more irregular shape，i.e. deviation from sphericity and more angular，can exert a higher pile tip resistance. Moreover，an iterative method is proposed to quantify the interaction of pile tip resistance，relative density，stress level and particle shape；and the predicted tip resistance derived from this method agrees well with the measured one.
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Received: 11 August 2010
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2011, Vol. 30 
