Uniaxial Mechanical Properties and Failure Characteristics of Fractured Silty Mudstone

Abstract

Cracking behaviour of silty mudstone with existing flaws can trigger slope instability. However, the mechanics of multi-fractured silty mudstone have not been adequately examined. To handle this issue, the study employs a comprehensive approach to investigate the mechanical characteristics and cracking mechanism of fractured silty mudstone combing uniaxial compression test conducted by similar material specimens, cracking strength model, macro damage model, and PFC. Similar material specimens containing prefabricated fractures are prepared using steel sheet insertion during curing. Results show that peak strength initially decreases and subsequently increases as the facture dip angle (β) increases, minimizing at 45° under uniaxial compressive load. The more fracture there exists, the greater reduction in peak strength. The failure morphology of fractured silty mudstone can be categorized into tensile failure, shear failure, and tensile-shear combined failure. Theoretical models confirm that the crack strength depends on β and fracture length (a), aligning with experimental results while crack strength exhibit inversely proportional to a. The simulation results are in good correlation with test results, verifying the reliability of the simulated approach combined with theoretical analysis. Overall, the novel contribution of this paper lies in the multilateral elucidation of the failure mechanism in silty mudstone containing multiple fractures.