Generalized Constitutive Model for Stabilized Quick Clay

G Grimstad,Pm Bujulu

doi:10.4314/gjer.v11i2.1

Abstract

An experimentally-based two yield surface constitutive model for cemented quick clay has been developed at NTNU, Norway, to reproduce the mechanical behavior of the stabilized quick clay in the triaxial p’-q stress space. The model takes into account the actual mechanical properties of the stabilized material, such as “attraction”, friction angle and destructuration. A further attempt has been made to extend the formulation into the full stress space, based on the Hardening Soil Model, the SClay Model, the Koiter Rule and two Mapping Rules. A generalized 3D-constitutive model for stabilized quick clay has been formulated. This paper discusses the formulation process and presents the resulting generalized model. Keywords: Constitutive model, Quick clay, Destructuration, Hardening rule, Yield surface

Highlights

Engineering properties of stabilized materials depend on the fabric and particle cementation resulting from the chemical reaction of the binders
Prediction of the mechanical behaviour of such materials has been formulated in form of a constitutive model (QUICKSTAB) as proposed by Bujulu and Grimstad (2012)
This paper discusses formulation of the generalized model based on the Hardening Soil Model (Brinkgreve et al 2006), the S-Clay1 model (Wheeler et al 2003), and formulations by Søreide (2002) and Dafalias and Manzari (2004)

Summary

INTRODUCTION

Engineering properties of stabilized materials depend on the fabric and particle cementation resulting from the chemical reaction of the binders. Where Μ (Greek capital μ) is an internal parameter related to the earth pressure coefficient under virgin loading, K0NC; pm’ is the size of the cap and ac is the attraction for the cap It may be shown, due to the strain requirement in oedometric condition and through an associated flow rule, that M will be given by Equation (2), assuming infinite elastic stiffness. The following softening rule for ac (Equation 4) was proposed due to the cap type plasticity (Bujulu and Grimstad, 2012). The cone yield surface appears in the p’– q stress space as a wedge, as expressed by Equation(5). The rule for adding response from several yield criteria and plastic potential functions is known as the Koiter rule (Schanz et al, 1999) This may be presented as Equation (11):. Where the plastic multiplier, dλi, is given by Equation (12):

Ai ì í î

CONCLUSION