Akademik Veri Yönetim Sistemi
CONSTRUCTION AND BUILDING MATERIALS, cilt.463, 2025 (SCI-Expanded)
In room and pillar mining, rooms cause stress redistribution, and pillars are prone to stress concentration and repetitive incoming pressures. Hence, pillars may spall along some key joints/fissures to form X-shaped broken pillars under high-stress conditions. This study uses mechanical tests and numerical simulations to reproduce strength characteristics and fissure evolution of X-shaped cracked rock pillars (X-CRP) covering different center diameters (D50) under uniaxial compression conditions from macro-mesoscopic perspectives. The research's conclusions are as follows: X-CRP shows obvious brittle characteristics under axial pressure, and the peak stresses of X-CRP-50 and X-CRP-20 correspond to maximum and minimum values of 95.2 MPa and 21.42 MPa, respectively, and peak stress drops by a decrease of D50; Variation of dissipated energy (ud) of X-CRP is related to stress-strain response, by high and low energy storage rates for X-CRP-20 and X-CRP-40, respectively. Numerical model outcomes specify that the force chain's strength and the particle vector velocity's magnitude are linked with D 50 and stress level, and the smaller the D50, the earlier the stress concentration appears and the larger the value. X-CRP's macroscopic failure style is allied by D50, X-CRP-50 exhibits tension-shear damage, X-CRP-40 and X-CRP-30 mainly reflect shear-tension damage, the upper part of which both produce large shear slip, and X-CRP- 20 produces transverse shear at D50, with a small area of shear surface, and the sample undergoes integral structural The results of the study can make up the blank of the complex mechanical properties and rupture behavior of X-CRP, and offer a basis for guessing service life and bearing capacity of underground X-shaped broken pillars, the selection of reinforcement method and support timing.