(1. Department of Geotechnical Engineering，College of Civil Engineering，Tongji University，Shanghai 200092，China；2. Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education，Tongji University，Shanghai 200092，China；3. Shandong Zhongjian Urban Development Co.，Ltd.，Ji'nan，Shandong 250014，China；
4. Shanghai Chengtou Group Co.，Ltd.，Shanghai 200020，China)
Abstract：The natural occurrence of numerous discontinuities in rock masses makes them prone to significant displacements and friction degradation under external dynamic forces，thereby increasing the risk of instability. Therefore，in order to explore the mechanical properties of jointed rock mass under the action of cyclic dynamics，this study focuses on natural red sandstone and explores the shear mechanical characteristics of rock discontinuities under cyclic shearing，considering the dynamic properties of rock masses by setting a high shear rate. The evolution of shear stress and normal displacement during cyclic shearing is revealed，and a peak shear strength prediction model for structural planes，incorporating the number of cyclic shearing cycles，is established based on plastic work theory. The results show that：(1) The applied cyclic shear rate(2 mm/s) reaches the dynamic range，and compared to quasi-static direct shear tests，this rate better simulates the shear mechanical behavior of discontinuities under dynamic conditions. (2) Under cyclic shearing，the number of cycles，type of discontinuities，and normal stress significantly affect the evolution of shear stress on the discontinuities. Normal displacement exhibits clear patterns at shear displacements of 0 mm and ±5 mm. With an increasing number of cycles，normal displacement gradually decreases，indicating a reduction in dilatancy and an increase in compaction. (3) A peak shear strength prediction model that considers the number of cyclic shear cycles is established，with an overall error of around 10% compared to actual conditions，demonstrating good applicability. The research findings provide theoretical support for the safety and stability assessment of rock engineering under dynamic disturbances.
张清照1，2，佟泽昊1，2，石振明1，2，谢可禄1，2，3，罗泽军1，2，4. 高循环剪切速率条件下岩石结构面动力学特性研究[J]. 岩石力学与工程学报, 0, (): 968-968.
ZHANG Qingzhao1，2，TONG Zehao1，2，SHI Zhenming1，2，XIE Kelu1，2，3，LUO Zejun1，2，4. Study on dynamic characteristics of rock discontinuities under high cyclic shear rate. , 0, (): 968-968.
