Behaviour of interfacial layer along granular soil-structure interfaces

Abstract

As shear occurs along a soil-structure interface, a localized zone with a thickness of several grain diameters will develop in soil along the interface, forming an interfacial layer. In this paper, the behaviour of a soil-structure interface is studied numerically by modelling the plane shear of a granular layer bounded by rigid plates. The mechanical behaviour of the granular material is described with a micro-polar hypoplastic continuum model. Numerical results are presented to show the development of shear localization along the interface for shearing under conditions of constant normal pressure and constant volume, respectively. Evolution of the resistance on the surface of the bounding plate is considered with respect to the influences of grain rotation.

Effects of periodic fluctuations of micro‐polar boundary conditions on shear localizations in granular soil–structure interaction

“…Figure 10 shows that the thickness of shear band (t) is larger where mean grain diameter is larger. The dependence of shear band thickness on mean grain diameter was similarly presented by Tejchman [3], Huang and Bauer [92], Huang et al [93], Tejchman et al [129]. The effect of mean grain diameter on shear band thickness was also observed in the experiments conducted by Roscoe [1] and DEM-simulation by Bardet and Proubet [111].…”

“…However, further investigations are needed for smooth and medium-rough interfaces where simultaneous slip and shear are expected [28]. In this regard, a kinematic relation should be used between boundary displacement and the corresponding Cosserat rotation [2,28,78,92,93]. In all calculations, the section with initial height of h 0 = 4 cm and width of b = 10 cm, is discretized by four-node elements of 1.25 mm×1.25 mm size.…”

“…However, such assumptions are not consistent with smooth and medium‐rough interfaces. For the mentioned cases, a certain coupling between the displacement of rigid body and the corresponding grain rotation should be considered along the interface 2, 28, 78, 92, 93.…”

Initial response of a micro-polar hypoplastic material under plane shearing

“…[38, pp. 79-85], [30,49,52]. Thus, the extreme value of the rate of micro-rotations obtained for the initial response (Figure 2c) is an indicator of where shear-strain localization may develop under continuous shearing.…”

“…The evolution of the state quantities are also determined by the height of the shear layer because the factor m 0 depends on h. By replacing m 0 with an arbitrary factor m relation (5.27) agrees with the empirical formula proposed by Tejchman [28] to model the influence of a rough bounding surface on the rotation resistance of particle in contact with the bounding structure. Numerical simulations by Huang et al [52] show that the location and thickness of shear-strain localization is strongly influenced by the value of the factor m. In particular for m = 0 the case of a very rough top surface without particle rotations is modeled which shows an extreme value of micro-rotations in the middle of the shear layer. For 0 < m < m 0 the extreme value of microrotations and consequently the location where shear-strain localization takes place is located within the upper part of the shear layer.…”