The definition of yield for bonded materials

The strength and deformation behaviour of a residual soil in Singapore

“…Substantial amount of stiffness has already been lost at the first yield point defined by Maccarini (1987) and Bressani (1990). As stated by Malandraki & Toll (1996), the second yield point determined from the E tan versus axial strain curve (log-log scale) coincided with the definition of "first yield" from Anagnostopoulos et al (1991), Kavvadas et al (1993Kavvadas et al ( , 1994 and "yield" from Coop & Atkinson (1993). The variation of the tangential stiffness provided a more accurate and simpler method to define yielding point, since the initiation of major loss in stiffness is distinctive.…”

“…After conducting a series of triaxial tests on carbonate sands, Coop & Atkinson (1993) observed a transitional failure mode when shearing at intermediate stress level. Malandraki & Toll (1996) verified their observation by testing an artificially bonded soil and a de-structured soil at different confining stress levels. Based on the test results on the artificially bonded soil (Malandraki, 1994), Malandraki & Toll (1996) identified four zones of behaviour from the relative positions of the failure surface and the second yield surface (as shown in Figure 2.21).…”

“…According to Smith et al (1992), it is always associated with a sharp change from elastic to plastic behaviour. However, in the historical development of soil mechanics, the traditional "yield" is used to describe a clear change in stress-strain behaviour (Malandraki & Toll, 1996). Vaughan (1985Vaughan ( , 1990) defined a yield stress as "a stress state at which a material shows a discontinuity in stress-strain behaviour under monotonic stress changes".…”

An anisotropic Model for Structured Soils

“…In bonded soils, initiation of structure yield is identifiable by a relatively abrupt drop in material stiffness (e.g. [21,22]). In unbonded overconsolidated materials, structure yield is associated with reaching the preconsolidation stress.…”

“…Loading from material states on the SSE causes appreciable rates of structure degradation and change of structure-induced anisotropy, associated with ''structure yield" [13] or ''bond yield" [22]. In bonded soils, initiation of structure yield is identifiable by a relatively abrupt drop in material stiffness (e.g.…”