A rheological constitutive model for damaged zone evolution of a tunnel considering strain hardening and softening
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ORIGINAL ARTICLE
A rheological constitutive model for damaged zone evolution of a tunnel considering strain hardening and softening Zhizeng Zhang . Xiaoli Liu Bing Zhang
. Lijuan Cheng . Shunchuan Wu .
Received: 9 May 2020 / Accepted: 17 September 2020 Ó Springer Nature Switzerland AG 2020
Abstract A rheological constitutive model for damaged zone evolution of a tunnel is proposed in this paper to describe the strain hardening and softening properties of the excavation-disturbed rock mass. Firstly, the one-dimension rheological model is introduced by connecting the improved St. Venant body with the Nishihara model, and this model can be used to describe the whole process including transient viscoplastic creep under a low-stress state, steadystate and accelerative creep under a high-stress state. Secondly, the constitutive equations of the rheological model under three-dimensional condition of the Z. Zhang College of Civil Engineering and Architecture, Zhongyuan University of Technology, Zhengzhou 450007, China X. Liu (&) Department of Hydraulic and Hydropower Engineering, Tsinghua University, Beijing 100084, China e-mail: [email protected] L. Cheng PowerChina Chengdu Engineering Corporation Limited, Chengdu 610072, Sichuan Province, China S. Wu Kunming University of Science and Technology, Kunming 650093, China
improved St. Venant body based on generalized plasticity potential theory are deduced, and the generic three-dimensional rheological model is developed. Thirdly, the creep and stress relaxation properties of the rheological model are studied and discussed. Furthermore, numerical analysis of triaxial compression tests and triaxial compression creep tests are conducted and the rheological model are validated. The results show that the rheological model can be used to study the evolution of excavation damaged zone in underground tunnel engineering. Keywords Tunnel Rheological model Strain hardening Strain softening Creep
1 Article Highlights 1. A rheological constitutive model for the damaged zone evolution of a tunnel was proposed. 2. 3D constitutive relations of the improved St. Venant body based on generalized plasticity potential theory were deduced. 3. Creep and stress relaxation properties of the rheological model were studied and discussed.
B. Zhang R&D Department, State Key Laboratory of Shield Machine and Boring Technology, Zhengzhou 450001, China
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Geomech. Geophys. Geo-energ. Geo-resour. (2020)6:56
2 Introduction Creep behavior of rock mass is a time-dependent deformation that relates to the stability of a tunnel (Sun et al. 2019). Low porosity rock mass has the following creep characteristics: rock mass under volume contraction will not experience creep failure while under volume dilatation will experience continued dilatation volumetric creep and shear creep which will end up with creep failure over time (Hunsche and Hampel 1999; Maranini and Yamaguchi 2001; Yang et al. 2015; Zhao et al. 2018; Tang et al. 2018; Wu et al. 2019). Constitutive models for
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