Modeling interaction between loading-induced and creep strains of rockfill materials using a hardening elastoplastic constitutive model

Abstract

An elastoplastic constitutive model that takes into account the stress–strain relationship and creep-induced hardening behavior of rockfill materials is proposed in light of previous experimental observations. It is assumed that the mechanical response during loading and the final amounts of creep strains under a constant stress state are independent of the strain rate. The focus of the proposed model is the coupling effect between loading and creep, including the influence of loading history on subsequent creep strains and the influence of creep history on subsequent loading behavior. An extended yield function, which allows flexible control over the shape of yield surfaces, is used not only to distinguish among loading, unloading, and neutral loading, but also to manipulate the creep-induced hardening using a plastic strains–based hardening parameter. A stress-dependent dilatancy equation is used, instead of a plastic potential function, to define the directions of plastic strains during loading. The hardening law is established based on three different types of experimental results. Only routine experiments are required for calibration of model parameters, and the model can be used in a reduced form according to the available test results. The model is verified using typical experimental data and is found to be capable of capturing important behavior of rockfill materials, such as pressure-dependent strength, shear contraction and dilation, and creep-induced stiffening.

Investigation of Lade‐Kim Plastic Potential Applicability under Various Stress Paths for Rockfill Materials

“…Paths. For conventional triaxial tests of rockfill materials, various dilatancy equations were proposed, such as linear dilatancy equation [22], Rowe dilatancy equation [1], modified Cambridge dilatancy equation [23], and Fu's dilatancy equation [24]. Few people pay attention to dilatancy equation under other stress paths, and the dilatancy equation derived from conventional triaxial tests is often applied into such paths in model verification.…”

“…e Lade-Kim dilatancy equation is equation (12) and the nonlinear dilatancy equation, similar to the one proposed by Fu et al [24], is listed as follows:…”

“…e parameters of the nonlinear dilatancy equation are obtained by arranging dg-η curves. e calibration methods of other model parameters are shown in the literature [24]. e parameters of generalized plasticity models using two kinds of dilatancy equations are listed in Table 1.…”

Effect of the Quasi Rate of Loading in Particle Crushing and Engineering Properties of Black Tough Sand

“…Past research has established that grain crushing is influenced by many factors. These factors are ranged from soil grain characteristics such as soil particle strength (Varadarajan et al 2006) angularity and morphology (Karatza et al, 2019;Xiao et al, 2019), or soil matrix properties such as gradation (Honkanadavar and Sharma, 2014), porosity (Hyodo et al, 2016), and moisture content (Alonso et al, 2016), and anisotropy (Hattamleh et al 2010, Hattamleh et al 2013) and external factors such as induced stress (Hattamleh et al 2010), loading duration (Fu et al, 2019), and loading rate (Huang et al, 2017 and;Parab et al, 2017).…”

The Constitutive Model of Rockfill Based on Property‐Dependent Plastic Potential Theory for Geomaterials

“…is has brought some difficulties in studying the constitutive relationship of rockfill. Some researchers have done a large amount of work and achieved positive research results such as the strainsoftening and dilatancy of rockfill [5], material constants and particle characteristics [6], load and creep [7,8], particle breakage and the relationship between intermediate principal stress coefficient b value and particle breakage [9], loading path [10], wetting deformation [11], the coupling effect of mean effective stress p and deviatoric stress q on deformation [12], and so on.…”