A new hydro-mechanical coupling constitutive model for brittle rocks considering initial compaction, hardening and softening behaviors under complex stress states

Autor: Zhi Zheng, Hao Su, Wei Wang, Zhechao Wang, Zaobao Liu, Benguo He, Guoxiong Mei
Rok vydání: 2023
Předmět:
Zdroj: Geomechanics and Geophysics for Geo-Energy and Geo-Resources. 9
ISSN: 2363-8427
2363-8419
DOI: 10.1007/s40948-023-00607-2
Popis: After the excavation of underground engineering, the failure and instability of surrounding rock under hydro-mechanical coupling conditions is a common type of engineering disaster. However, the hydro-mechanical coupling mechanical characteristics of rock have not been fully revealed, and suitable models for the stability analysis of surrounding rock under hydro-mechanical coupling conditions are very scarce. Therefore, a series of triaxial compression and cyclic loading and unloading hydro-mechanical coupling tests were carried out to study the mechanical characteristics, deformation and mechanical parameters of rock under different confining pressures and pore pressures. Then, based on Biot’s effective stress principle, a hydro-mechanical coupling damage constitutive model within the framework of irreversible thermodynamics was proposed to describe the initial compaction effect, pre-peak hardening and post-peak softening behaviors. The functional relationships between the proposed model key parameters (η and ζ) and the effective stress were established to characterize the pre- and post-peak nonlinear behaviors of rock. A compaction function Ck for the evolution of the undamaged Young’s modulus in initial compaction stage was introduced to characterize the pre-peak compaction effect. A user-defined material subroutine (UMAT) was compiled in ABAQUS to numerically implemented the proposed model. The numerical simulation results are highly consistent with the test results, the proposed model can also predict the hydro-mechanical coupling characteristics of rock under untested stress levels. In addition, the yield function of the proposed model considers the influence of intermediate principal stress, which is also suitable for the simulation of hydro-mechanical coupling characteristics under true triaxial stress states. Graphical abstract
Databáze: OpenAIRE
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