Work

Constitutive damage model for foliated slate under dynamic loading

Year: 2025

Type: article

Abstract: Foliated rock exhibits pronounced mechanical anisotropy due to inherent weaknesses along foliation planes. The orientation of these planes critically influences the dynamic mechanics of foliated rock, making it a key factor in the stability and safety of rock engineering projects. This research investigated the effects of foliation dip angle ( θ ), and strain rate ( ) on the dynamic mechanical behavior of the slate through dynamic unconfined compression tests using a split-Hopkinson pressure bar (SHPB). The experimental results indicate that increasing the strain rate enhances the material strength, leading to higher peak stress, greater energy absorption, and more extensive fracturing. Observations of the failure modes reveal that the orientation of foliation planes and strain rate significantly influence the failure modes. When the foliation planes are perpendicular to the axial load at θ = 0°, failure at low strain rates is mainly caused by stress wave reflection along the foliation planes. At high strain rates, the failure is dominated by impact-induced splitting. At oblique orientations ( θ = 30°, 45°, and 60°), increasing the dip angle causes a transition from axial splitting to shear failure along the foliation planes. When the foliation planes are parallel to the axial load ( θ = 90°), failure is entirely governed by tensile fracturing along the foliation planes. Based on the experimental results, a constitutive model is developed to characterize the influence of foliation dip angle and strain rates on dynamic mechanics of foliated rock. The model consists of micro-units characterized by an orientation factor ( D ) for foliation-induced anisotropy and a dynamic viscosity coefficient ( η ) for strain rate effects. The strength of micro-units follows a Weibull distribution, capturing the microstructural variability. Parameter sensitivity, calibration methods and model limitations are discussed in detail. Overall, this model provides a robust framework for understanding and predicting the dynamic mechanical behavior of foliated slate.

Source: Journal of Rock Mechanics and Geotechnical Engineering

DOI: 10.1016/j.jrmge.2025.07.030

Authors: Xuefeng Ou, Shiquan Xu, Qinxin Hu, Huicong Xu, Cong Tang

Institutions: Changsha University of Science and Technology, University of Strathclyde

Language: English

Topic: Rock Mechanics and Modeling

Subfield: Mechanics of Materials

Field: Engineering

Domain: Physical Sciences

Open Access status: diamond

Funders: National Natural Science Foundation of China, Natural Science Foundation of Hunan Province

Awards: G1050606551, G7740651397