TY - JOUR

T1 - A multiscale poroelastic damage model for fracturing in permeable rocks

AU - Yang, Jianxiong

AU - Liu, Jianfeng

AU - Li, Wenfeng

AU - Dai, Jingjing

AU - Xue, Fujun

AU - Zhuang, Xiaoying

N1 - Funding Information: This research was financially supported by the National Natural Science Foundation of China (Grant No. 12302503 , U20A20266 ) and the Scientific and technological research projects in Sichuan province (Grant No. 2023ZYD0154 , 2024GJHZ0035 ).

PY - 2024/3

Y1 - 2024/3

N2 - A new poroelastic damage model is developed in the paper to describe the macroscopic failure of rock materials due to microcrack nucleation and propagation based on a multiscale framework. The model is deduced from locally periodic microstructure with dynamically evolved microcracks in heterogeneous rock body. The homogenization method based on asymptotic expansions gives rise to the damage evolution law coupled with the poroelastic fracture system, which includes the fracture opening induced permeability change. The obtained model takes into account the complex coupling between fluid pressure-deformation and hydro-mechanical (HM) properties at the microscale, leading to the nonlinear anisotropic mechanical behavior, degradation of both elastic stiffness and poroelastic properties at the macroscale, which is fundamental to describe the complex fracturing behavior influenced by microcrack distribution. The homogenized coefficients are illustrated in detail for a given set of initial material parameters, with dependence on the normalized damage variable. Results of numerical simulations well reproduce specific experimental observations where fracturing in heterogeneous rocks is shown to be a multiscale phenomenon that initiates from the microcrack nucleation and propagation, while the fracture propagation direction is shown to be influenced by both external loadings and microcrack distribution. The easy implementation in finite element framework and revealed micro-mechanism for macroscopic failure under strict mathematical formulations make the wide application of model in rock mechanics problems.

AB - A new poroelastic damage model is developed in the paper to describe the macroscopic failure of rock materials due to microcrack nucleation and propagation based on a multiscale framework. The model is deduced from locally periodic microstructure with dynamically evolved microcracks in heterogeneous rock body. The homogenization method based on asymptotic expansions gives rise to the damage evolution law coupled with the poroelastic fracture system, which includes the fracture opening induced permeability change. The obtained model takes into account the complex coupling between fluid pressure-deformation and hydro-mechanical (HM) properties at the microscale, leading to the nonlinear anisotropic mechanical behavior, degradation of both elastic stiffness and poroelastic properties at the macroscale, which is fundamental to describe the complex fracturing behavior influenced by microcrack distribution. The homogenized coefficients are illustrated in detail for a given set of initial material parameters, with dependence on the normalized damage variable. Results of numerical simulations well reproduce specific experimental observations where fracturing in heterogeneous rocks is shown to be a multiscale phenomenon that initiates from the microcrack nucleation and propagation, while the fracture propagation direction is shown to be influenced by both external loadings and microcrack distribution. The easy implementation in finite element framework and revealed micro-mechanism for macroscopic failure under strict mathematical formulations make the wide application of model in rock mechanics problems.

KW - Damage law

KW - Heterogeneous rock

KW - Homogenization

KW - Microcrack

KW - Multiscale fracturing

UR - http://www.scopus.com/inward/record.url?scp=85186445021&partnerID=8YFLogxK

U2 - 10.1016/j.ijrmms.2024.105676

DO - 10.1016/j.ijrmms.2024.105676

M3 - Article

AN - SCOPUS:85186445021

VL - 175

JO - International Journal of Rock Mechanics and Mining Sciences

JF - International Journal of Rock Mechanics and Mining Sciences

SN - 1365-1609

M1 - 105676

ER -