As the loading progressed, the particles in the middle of the model moved outward due to pressure, resulting in the dilatancy of specimens in the middle of the model, which was the same as the failure mode (Figure 10) of samples in the indoor test.

Yuan and Harrison [6] proposed the local degradation method, in which the hydromechanical coupling with evolutions of element's permeability and dilatancy was considered.

Probably the temperature variation does not directly affect the H/V amplitude but is responsible of other mechanisms like: (i) increasing of the fracturing degree of the medium acting directly on the dilatancy of the rocks (an increase in the medium fracturing may result, directly or, more often, indirectly, in density or velocity of propagation variations); (ii) influencing the water content of the superficial layer leading to an increase of the wave velocity of this portion of the slope.

When volume fractions are high and distributions are narrow, dilatancy, and shear-thickening effects are observed [10-18], Particle clusters that block the flow are formed, leading to instabilities.

During compression in different confining pressure and tension in different strain rate and different temperature, the volume strain is always characterizes negative and positive dilatancy shown in Fig.

(1978) Dilatancy and fracture-induced velocity changes in rock and their relation to frictional sliding.

It is obvious that these materials should be treated as discrete elements, and that the mechanical properties of these materials depend on properties of individual particles, thereby, some of them such as packing density, flowability, dilatancy, crushability, friction, etc., are highly contributed by the particle shape.

It was found that high reactivity aggregates pronounced by high mortar bar dilatancy result in significant decrease of P-wave velocity and high ultrasonic signal attenuation.