<p>This thesis investigates the effects of sample preparation methods, which has substantial influence on the internal structure or fabric of the sample, and interparticle locking on the behaviour of sand through experimental study. Extensive laboratory tests were conducted on two sands (namely, Ottawa sand and crushed limestone) with distinct particle shape and surface texture, using a Bishop-type triaxial testing system.</p><p>A total of eight sample preparation methods were used to fabricate specimens with different initial fabric, with specimens being fabricated using water pluviation, moist tamping, and moist rodding. The experimental data reveal that sample preparation methods have significant effect on both deformation characteristics and shear strength of sand, in addition to the density and the effective confining pressure applied to the specimens. More specifically, water pluviation and moist tamping tend to yield specimens of high anisotropy and large dilation, which in turn results in higher friction angle in conventional triaxial compression. The effect of sample preparation methods was also observed from undrained tests on saturated sand.</p><p>Laboratory tests on crushed limestone consisting of angular particles demonstrate that strong interparticle locking may develop owing to particle angularity. The shear resistance of sand with angular particles has contributions from interparticle friction, dilatation and interparticle locking. Moreover, interparticle locking, which largely exists at the peak shear resistance of sand but vanishes with dilation at large deformation, exists under both low and high stress levels investigated in this study. A conceptual model was proposed to take into account the energy consumption associated with breaking interparticle locking during deformation when estimating the dilatancy and strength of granular soils.</P><P>The behaviour of sand along proportional strain paths was also investigated, with the focus being placed on strain softening and material instability in the context of Hill's second order work. Depending on the strain path or the deformation history, a dilatant sand displaying hardening and stable behaviour under isochronic (undrained) conditions, which is often used as a reference in soil mechanics, may succumb to unstable flow type behaviour along dilative strain paths. More specifically, when the imposed rate of dilation exceeds the inherent rate of dilation of the material, a dense sand specimen will have flow failure similar to that of a saturated loose specimen subjected to undrained compression. On the other hand, a loose sand may not have a flow failure when it is forced to have contractive volume change along imposed strain paths.</P> / Thesis / Master of Science (MSc)