Mechanical Properties of Unsaturated Low Quality Rockfills

An Elastoplastic Model for Unsaturated Rockfills and its Simulations of Laboratory Tests

“…An example of relationships between compression loads (breakage strength) and water contents for rock particles can be seen in Fig. 2 (Kohgo et al, 2007). The breakage strength of rock particles may mostly decrease with an increase in water content or a decrease in suction, so more external loads need to be applied to unsaturated rockˆll specimens than those to saturated ones to induce the same plastic deformations.…”

“…In rockˆlls, if suction is applied from the full saturation condition, the saturation condition will immediately come into the pendural saturation condition by small application of suction as shown in Fig. 4 where symbols express mean experimental values obtained from the soil column tests (Kohgo et al, 2007). Then, it is su‹cient to take only the second suction eŠect into account when suction is higher than air entry suction.…”

“…5. Figure 5 shows typical results of triaxial compression tests for saturated and unsaturated (air dry) specimens (Kohgo et al, 2007). Theˆrst suction eŠect may be evaluated by using the relationship between suction and shear strength values at the critical state (Kohgo et al, 1993a).…”

“…In order to verify the elastoplastic model, we conducted the simulations of the oedometer and triaxial compression tests of a rockˆll named Material S (Kohgo et al, 2007). The K-G model was adopted to express the elastic properties.…”

“…The breakage properties are sometimes strongly aŠected by the degree of saturation (Terzaghi, 1960;Kohgo et al, 2007). Especially, compression deformations due to saturation, called saturation collapse, seems to be induced by the diŠerence between saturated and unsaturated breakage properties of rock particles.…”