Dilatancy

Dilatancy in slow granular flows.

When walking on wet sand, each footstep leaves behind a temporarily dry impression. This counterintuitive observation is the most common illustration of the Reynolds principle of dilatancy: that is, a granular packing tends to expand as it is deformed, therefore increasing the amount of porous space. Although widely called upon in areas such as soil mechanics and geotechnics, a deeper understan...

Dilatancy Transition in a Granular Model

We introduce a model of granular matter and use a volume/strain ensemble to analyze infinitesimal shearing. Monte Carlo simulation suggests the model exhibits a second order phase transition associated with the onset of dilatancy.

Shear-induced dilatancy of fluid-saturated faults: Experiment and theory

[1] Pore fluid pressure plays an important role in the frictional strength and stability of tectonic faults. We report on laboratory measurements of porosity changes associated with transient increases in shear velocity during frictional sliding within simulated finegrained quartz fault gouge (d50 = 127 mm). Experiments were conducted in a novel true triaxial pressure vessel using the double-di...

Shear modulus and dilatancy softening in granular packings above jamming.

We investigate experimentally the mechanical response to shear of a monolayer of bidisperse frictional grains across the jamming transition. We inflate an intruder inside the packing and use photoelasticity and tracking techniques to measure the induced shear strain and stresses at the grain scale. We quantify experimentally the constitutive relations for strain amplitudes as low as 10(-3) and ...

Flowing resistance and dilatancy of dense suspensions: lubrication and repulsion