A two-surface thermomechanical plasticity model considering thermal cyclic behavior
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RESEARCH PAPER
A two-surface thermomechanical plasticity model considering thermal cyclic behavior Wei Cheng1 • Ren-peng Chen1,2
•
Peng-yun Hong3 • Yu-jun Cui3 • Jean-Michel Pereira3
Received: 3 September 2019 / Accepted: 27 May 2020 Ó Springer-Verlag GmbH Germany, part of Springer Nature 2020
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 thermo-mechanical 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 fine-grained soils under the effect of thermal cycles. Keywords Excess pore water pressure buildup Fine-grained soils Strain accumulation Thermal cycles Two-surface model List of symbols a0 Parameter controlling thermal plastic behavior a1 Parameter controlling thermal elastic behavior b The size parameter of potential plastic surface k, j Slope of isotropic loading, reloading line, respectively
t, m Ad de, dr, dT deer , deeT dev , deev , dees dep , depv , deps
& Ren-peng Chen [email protected]; [email protected] Wei Cheng [email protected] 1
Department of Civil Engineering, Zhejiang University, Hangzhou 310058, China
2
College of Civil Engineering, Hunan University, Changsha 410082, China
3
Laboratoire Navier (UMR 8205) CNRS, Ecole des Ponts, Univ Gustave Eiffel, 77455 Marne-la-Valle´e, France
K fI, fY G, K, h k f, k g
Mf
Current void ratio, Poisson’s ratio, respectively Parameter controlling the contribution of shear plastic strain Total strain, stress, temperature increment respectively Stress, thermal-induced elastic strain increment, respectively Total volumetric, elastic volumetric, shear strain increment, respectively Plastic, plastic volumetric, plastic shear strain increment, respectively Plastic multiplier Loading surface, y
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