Dynamic mechanical behaviors of pre-fractured sandstone with noncoplanar and unparallel flaws. (March 2022)

• Record Type: Journal Article
• Authors: Feng, Peng; Dai, Feng; Shuai, Kewei; Wei, Mingdong
• Is Part Of: Mechanics of materials. Volume 166(2022)
• Publication Date: 2022-03
• Subjects: Unparallel-flawed rock -- Mechanical properties -- Strain rate dependence -- Fragmentation -- Energy dissipation; Strength of materials -- Periodicals; Mechanics, Applied -- Periodicals; Résistance des matériaux -- Périodiques; Mécanique appliquée -- Périodiques; Mechanics, Applied; Strength of materials; Periodicals; Electronic journals; 620.11
• DOI: 10.1016/j.mechmat.2022.104219
• Languages: English
• ISSNs: 0167-6636

Abstract

Abstract: Field rock masses with irregular flaws are often vulnerable to dynamic damage caused by excavation, drilling and earthquake. Investigating the mechanical behaviors of flawed rocks with dynamic loads is essential for the design of rock engineering facilities. However, the fracturing mechanism and fragment characteristics of flawed rocks have not been fully revealed, especially for brittle rocks with unparallel and noncoplanar flaws. This study systematically investigates the static and dynamic mechanical behaviors of sandstone with noncoplanar and unparallel flaws. A loading-rate dependence of the strength, fractal characteristics and energy dissipation of the pre-fractured sandstone is demonstrated. The dynamic strength of unparallel-flawed sandstones behaves more sensitive to the strain rate than that of noncoplanar-flawed sandstones. The failure modes of the specimens under static compression are primarily controlled by tensile cracks, while shear cracks mainly effect the dynamic failure patterns. Under low dynamic strain rates, the specimens mainly break into columnar or lamellar structures with a significantly non-uniform size distribution, accompanied by a relatively small amount of energy dissipation. At high dynamic strain rates, the flawed rocks experience severe damage and break into many small fragments with relatively uniform sizes, associated with comparably high energy dissipation. Highlights: Conducted the dynamic compression tests on sandstone specimens with noncoplanar flaws and unparallel flaws. Revealed the dynamic strain rate dependency of mechanical properties of sandstone specimens with noncoplanar flaws and unparallel flaws. Observed different fragment characteristics of sandstone specimens with noncoplanar flaws and unparallel flaws under different dynamic loads. Reported the effects of dynamic strain rates on the energy dissipation of sandstone specimens with noncoplanar flaws and unparallel flaws.