Monotonic and cyclic constitutive law of interface between structure and coarse grained soil

Systematic tests were conducted to investigate constitutive rule of the interface between structure and coarse grained soil. Based on macro- and micro-observation, five essential constitutive rules could be induced to characterize the monotonic and cyclic behavior of such interface. The constitutive rules includes: (1) the shear strength is nearly proportional to normal stress; (2) the shear stress would increase and tend to a stable value with the development of shear strain due to a monotonic stress path application under constant normal stress condition; (3) the volumetric strain due to dilatancy is composed of a reversible and an irreversible dilatancy component. The reversible dilatancy component obviously exhibits anisotropical behavior. The shear strain component related to the volumetric strain due to dilatancy exhibits a variable proportion in total shear strain during shear application; (4) the compressibility decreases with the increase of normal stress; (5) the physical state and mechanical behavior evolve and tend to be stable during shear application.