Abstract: The reinforcement could increase the shear strength of soil and reduce the deformation of soil. Polyurethane foam adhesive (PFA) is adopted to reinforce rockfill materials. A series of triaxial shear tests on the PFA-reinforced rockfill materials is conducted. The test results show that the PFA-reinforced rockfill materials exhibit a nonlinear deviatoric stress-axial strain behavior. The shear strength increases with increasing the PFA ratio. A parabola formula is used to fit the deviatoric stress-axial strain curve and reflect the strain softening and hardening behaviors of the PFA-reinforced rockfill materials. The initial elastic modulus of the PFA-reinforced rockfill materials increases with increasing the PFA ratio. The mechanical effect of the PFA is to fill the voids among particles and then to bond the particles. As a result, the particle breakage and rearrangement reduce and the feature of volumetric shrinkage decreases. The dilatancy behavior increases with increasing the PFA ratio. Adding PFA into rockfill materials can enhance the cohesion, but it has no obvious effect on the frictional angle. The deformation and stability of a dam are analyzed using the finite element method. It is shown that the PFA-reinforced method can largely reduce the shallow slide of slope, enlarge the depth of the slip circle and increase the stability of rockfill dam.

Key words: rockfill materials, polyurethane, triaxial tests, shear strength, dilatancy