Mechanical behavior and energy evolution in fractured stone relics under compression-shear: Implications for heritage conservation and rock mass stability

Stone cultural relics are non-renewable cultural heritage, and their long-term preservation is confronted with the risks of crack development and structural instability. This study investigates how the geometry of pre-existing cracks governs energy-transfer pathways and macroscopic failure modes in stone containing penetrating coplanar flaws. Compression-shear tests were conducted on cubic stone specimens representative of the lithology found in Zhangcun Township’s architectural relics. Results demonstrate that flaw inclination fundamentally governs the mixed-mode fracture condition by modulating the stress decomposition on the rock-bridge cross-section. As the inclination increases from 0° to 30°, transitioning the dominant fracture mechanism from pure shear to a coupled compression-shear condition; increasing rock-bridge length from 15 mm to 35 mm raises the peak elastic-strain-energy density by 62%. This work provides a mechanical basis for diagnosing propagation risks and designing targeted repair strategies for the conservation of architectural stone heritage.