نوع مقاله : مقاله پژوهشی
نویسندگان
1 Department of Mining Engineering, Faculty of Engineering, University of Kashan, Kashan, Iran
2 Department of Mining Engineering, Urmia University, Urmia, Iran
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Accurate prediction of the mechanical behavior of infilled jointed rock under triaxial compression remains a major challenge in rock engineering because of the complex interactions among joint roughness, infill thickness, and orientation. Although these factors have been extensively investigated individually, their combined influence has not yet been systematically quantified within a calibrated three-dimensional micro–macro framework. This study presents an integrated experimental–numerical investigation to evaluate the coupled effects of joint roughness morphology, infill thickness, and orientation on the triaxial compressive strength (TCS) of infilled jointed rock. Triaxial compression tests were conducted on specimens containing three infill thicknesses (3, 5, and 8 mm), two representative roughness morphologies (tooth-shaped and undulating), and joint orientations ranging from 0° to 90° under confining pressures of 5 and 14 MPa. A three-dimensional discrete element model based on PFC3D was developed and calibrated using both uniaxial and triaxial laboratory test results. The calibration procedure established a consistent micro–macro relationship capable of reproducing the mechanical behavior of both intact and jointed rock specimens. Numerical predictions showed excellent agreement with experimental observations, reproducing peak strengths and complete stress–strain responses with relative deviations of less than 3%. The results indicate that the minimum TCS consistently occurs at intermediate joint orientations (approximately 30°-45°), where shear-dominated failure mechanisms become predominant. Increasing the confining pressure from 5 MPa to 14 MPa enhanced strength by approximately 120% in intact rock and by 94-118% in jointed specimens, demonstrating the dominant role of confinement in suppressing instability. The reduction in strength caused by increasing infill thickness was pronounced under low confinement but became less significant at higher confinement levels. Furthermore, the contribution of surface roughness was found to be confinement dependent: asperity interlocking improved strength under low normal stress, whereas matrix-controlled resistance increasingly governed the mechanical response as confinement increased. By integrating joint roughness, infill thickness, and orientation within a three-dimensional DEM framework, this study provides a physically based and validated approach for evaluating discontinuity-controlled strength under triaxial loading conditions. The proposed methodology offers a reliable tool for stability assessment and design of underground excavations, rock slopes, and other rock engineering structures.
کلیدواژهها [English]
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