Undrained monotonic and cyclic shear response and particle crushing of silica sand at low and high pressures

Abstract

A series of undrained monotonic and cyclic triaxial tests were performed on silica sand at two initial densities and different confining pressures from 0.1 to 5 MPa to investigate their shear response and crushing behaviour. The influence of particle crushing on the undrained shear strength and pore-water pressure was examined. To clarify the evolution of particle crushing, undrained monotonic and cyclic tests were terminated at several distinctive stages and sieving analysis tests were subsequently performed on the tested specimens. In the undrained monotonic test, specimens exhibited remarkable dilation behaviour and experienced no apparent particle crushing at low confining pressures. An increase in the mean stress suppressed the dilatancy due to a faster increase of the pore-water pressure, giving rise to the occurrence of particle crushing. In the undrained cyclic test, a higher confining pressure and cyclic stress ratio resulted in a much higher relative breakage. At a specific cyclic stress ratio, the relative breakage increased as the cyclic loading progressed. The confining pressure and shear strain amplitude played a significant role in controlling the evolution of particle breakage. The correlation between the relative breakage and plastic work for specimens under isotropic consolidation, undrained monotonic, and cyclic loadings has been validated experimentally.

Numerical Simulation of Particle Breakage of Granular Assemblies in Discrete Element Analyses

“…In the initial stage, particle breakage is very small and it occurs at certain energy, which increases from the beginning of isotropic compression. e result is consistent with the experimental observation by Yu [12], Hyodo et al [18], and DEM result simulated by Liu et al [53]. e data distribution may be fitted well by a hyperbolic equation of the following form:…”

“…Coop et al found that a constant grading can be reached at very large strains on carbonate sands, even quartz sands at low stress levels, were subjected to small amounts of particle breakage [15,16]. Wu et al [17] and Hyodo et al [18] found that the large amount of particle breakage resulting from the high-level strain was induced by particle transformation and rotation during shearing. Yu [12] conducted a great deal of triaxial tests under various influence factors (e.g., confining pressure, initial void ratio, and drainage condition) and discussed the effects of these factors on particle breakage and whole volume change.…”

Impacts of hydrate on the lateral stress in sediments

“…The hydrate crystals can enhance the strength and the stiffness of hydrate-bearing specimens [15][16][17]. The reduction of Ko for the Sh = 0.96 specimen under relatively low vertical stress (σv < 1 MPa) is primarily caused by the cementation between soil particles and hydrate crystals.…”

Simple Modelling of Undrained Shear Response of Granular Materials

“…p cr refers to the mean stress when the peak stress ratio reduces to the stress ratio at the critical state. The peak stress ratio η p only emerges for the soil at the dense state [22][23][24]. η p approaches to η cr at the critical state as the mean stress p is increased to be identical to p cr .…”