Non-linear elastic model incorporating temperature effects

Abstract

The objective of this paper is to present a non-linear elastic model, considering temperature effects, that engineers can readily use to predict the mechanical behaviours of soils in geotechnical applications. Instead of using hyperbolic and exponential models, a non-linear equation is first formatted to describe the tangent moduli for saturated clays by introducing only one additional parameter (i.e. p ). By extending the non-linear equation, a new simplified nonlinear elastic model is obtained that is capable of capturing well the stress-strain relationship of saturated clays at room temperature. Thereafter, based on experimental results, the relationships between cohesion, internal friction angle, index, tangent bulk modulus and temperature are developed and incorporated in the non-linear elastic model. A revised semi-regression method is also developed to determine the relationship between the additional model parameter p and temperature. In this model, all of the eight parameters for the model have clear physical meanings and could be readily obtained by performing temperature-controlled triaxial tests. The accuracy and general applicability of the proposed method was checked by comparing its predictions with experimental results on saturated clay under various stress-path and temperature conditions as well as existing solutions proposed elsewhere. et al., 1989;Rao et al., 2017;Sun et al., 2011), energy piles (Abdelaziz and Ozudogru, 2016;Knellwolf et al., 2011;Saggu and Chakraborty, 2016) and geothermal structures (Brandl, 2006), highway pavements (Bianchini et al., 2011;Kertesz and Sansalone, 2014), thermally active embankments (Coccia and McCartney, 2013) and thermally active retaining walls (Stewart et al., 2014).The volume change for saturated soils performs a transition from contractive to expansive behaviour during drained heating or the temperature cycle with increasing overconsolidation ratio (O CR ) (Abuel-Naga et al., 2006;Baldi et al., 1988;Cekerevac and Laloui, 2004;Romero et al., 2005) or relative density (Ng et al., 2016). Some experimental test results showed that the shear strength of saturated clays under both drained and undrained conditions would increase with increase in temperature (Abuel- However, most of these temperature-dependent constitutive models mentioned previously are based on the elasto-plastic Camclay or modified Cam-clay model in the critical state framework. These models often include a number of parameters which may not have physical meanings or that have values difficult to determine due to the complicated soil properties, particularly considering the effects of temperature. Compared with these elastic-plastic models, it is easier to understand the theory of nonlinear elastic models, and the parameters could also be easily determined by performing triaxial compression tests Chang, 2006, 2008). In addition, the non-linear elastic models (e.g. Duncan-Chang model) could be readily implemented in finite-element analysis software without a singular matrix (Chen and Liu, ...

Machine learning approaches to estimation of the compressibility of soft soils

“…Amiri et al (2018) used multiple linear regression to estimate unsaturated shear strength parameters using several indices of the physical properties of soil as function inputs. Liu et al (2018) reported on the relationships between the mechanical properties of clays and temperature. Motaghedi and Eslami (2014), Mcgann et al (2015), Cao and Wang (2013), Lim et al (2020), and Schneider et al (2008) empirically linked data from CPT on sleeve friction, cone tip resistance, and porewater pressure data to soil properties including cohesion, friction angle, soil classification, overconsolidation ratio, and shear wave velocity.…”

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“…Lo et al (2016) presented a one-dimensional consolidation theory in unsaturated soils under cyclic loading. Wang et al (2017), Liu et al (2018), Zou et al (2018), and Zhao et al (2020), respectively, obtained analytical solutions for the one-dimensional consolidation of clayey soils considering different load and boundary conditions. When considering time-dependent loading, Deng et al (2019) presented closedform solutions for one-dimensional consolidation in saturated soils, Moradi et al (2019) analyzed the one-dimensional consolidation of a multilayered unsaturated soil under partially permeable boundary conditions, and Zhou et al (2020) obtained an analytical solution for a classical one-dimensional thaw consolidation model.…”

Editorial

“…Based on environmental tests, the sediments were assessed as uncontaminated and could be reused directly without a decontamination treatment process. Liu et al (2018a) developed a non-linear elastic model, considering temperature effects that engineers can readily use to predict the mechanical behaviours of soils in geotechnical applications. In this model, all of the eight parameters have clear physical meanings and could be readily obtained by performing temperature-controlled triaxial tests.…”