A two-surface thermomechanical plasticity model considering thermal cyclic behavior

Abstract

In thermal-related engineering such as thermal energy structures and nuclear waste disposal, it is essential to well understand volume change and excess pore water pressure buildup of soils under thermal cycles. However, most existing thermomechanical models can merely simulate one heating-cooling cycle and fail in capturing accumulation phenomenon due to multiple thermal cycles. In this study, a two surface elasto-plastic model considering thermal cyclic behavior is proposed. This model is based on the bounding surface plasticity and progressive plasticity by introducing two yield surfaces and two loading yield limits. A dependency law is proposed by linking two loading yield limits with a thermal accumulation parameter nc, allowing the thermal cyclic behavior to be taken into account. Parameter nc controls the evolution rate of the inner loading yield limit approaching the loading yield limit following a thermal loading path. By extending the thermo-hydro-mechanical equations into the elastic-plastic state, the excess pore water pressure buildup of soil due to thermal cycles is also accounted. Then, thermal cycle tests on four fine-grained soils (natural Boom clay, Geneva clay, Bonny silt and reconstituted Pontida clay) under different OCRs and stresses are simulated and compared. The results show that the proposed model can well describe both strain accumulation phenomenon and excess pore water pressure buildup of finegrained soils under the effect of thermal cycles.

Rheological consolidation analysis of saturated clay ground under cyclic loading based on the fractional order Kelvin model

“…27,28 Scholars have conducted many beneficial studies on the static consolidation characteristics of clay-based on fractional order rheological models in recent years. [29][30][31] Under cyclic dynamic loading, the accumulation and dissipation of pore water pressure in saturated clay will occur cyclically, and the rheology of the soil skeleton and the permeation of pore water act simultaneously. Therefore, the dynamic consolidation of saturated clay will have more complex properties.…”

“…Related experimental results have demonstrated that compared with traditional integer order models, the fractional order rheological model proposed by Blair 25 and Gerasimov 26 has better applicability to clay 27,28 . Scholars have conducted many beneficial studies on the static consolidation characteristics of clay‐based on fractional order rheological models in recent years 29–31 …”

A thermomechanical model for argillaceous hard soils - weak rocks: application to THM simulation of deep excavations in claystone

“…In fact, adopting similar assumptions, most subsequent models are based on the same principle (Robinet et al, 1996;Modaressi and Laloui, 1997;Cui et al, 2000;Graham et al, 2001;Abuel-Naga et al, 2009;Laloui and François, 2009;Yao, Y. and Zhou;Di Donna and Laloui, 2015;Hamidi et al, 2015;Tourchi and Hamidi, 2015;Zhou C and Ng CW., 2015;Hamidi et al, 2017;Hamidi and Tourchi, 2018;Maranha et al, 2018). In the meantime, the concept of bounding surface plasticity has also been extended to improve the modelling of cyclic behaviour at various temperatures and volume change under thermal loading at intermediately and highly overconsolidated states (Modaressi and Laloui, 1997;Laloui and Cekerevac, 2008;Laloui and François, 2009;Di Donna and Laloui, 2015;Zhou et al, 2017;Zhou and Ng, 2018;Cheng et al, 2020;Golchin et al, 2022a,b).…”

A thermal state‐dependent bounding surface model for volume change of clay

“…To improve the prediction of the accumulation of plastic strain under temperature cycles, a typical approach is adding a thermal accumulation parameter. 14,21 On the other hand, Zhou et al 22 introduced a memory surface into the bounding surface model. However, these models fail to predict the irreversible thermal expansion of heavily OC soils as observed in experiments.…”

“…The experimentally observed irreversible volumetric strain accumulates but at a reduced rate during the thermal cycles, 13 which cannot be well captured by these constitutive models. To improve the prediction of the accumulation of plastic strain under temperature cycles, a typical approach is adding a thermal accumulation parameter 14,21 . On the other hand, Zhou et al 22 .…”