周期荷载作用下冻融裂隙砂岩变形破坏机理  

Deformation and Failure Mechanism of Freeze-thaw Fractured Sandstone under Cyclic Loading

作　　者：任建喜[1] 宋嘉炜 张琨[1] 张凡 谭牧凡 REN Jian-xi;SONG Jia-wei;ZHANG Kun;ZHANG Fan;TAN Mu-fan(Department of Architecture and Civil Engineering,Xi'an University of Science and Technology,Xi'an 710054,China)

机构地区：[1]西安科技大学建筑与土木工程学院,西安710054

出　　处：《科学技术与工程》2024年第14期5943-5950,共8页Science Technology and Engineering

基　　金：国家自然科学基金(12072259)。

摘　　要：为研究裂隙岩体在冻融与周期荷载作用下的变形破坏机理,采用宏观周期荷载试验与细观核磁共振试验以及颗粒流数值模拟相结合的方法,对不同冻融循环次数作用下裂隙砂岩的宏细观破坏机理进行研究。结果表明:冻融次数的增加使裂隙砂岩强度降低,破坏时扩容现象加剧,细观尺度上表现出孔隙尺寸及数量增加;冻融及周期荷载耦合作用使裂隙砂岩破坏裂纹发展多且复杂,破坏程度更严重,细观表现为T_(2)谱峰总面积变化率增幅更加显著、大尺度孔隙占比增加;周期荷载作用下裂隙砂岩的变形曲线趋势可作为判断疲劳强度门槛值范围的依据,获取变形预警值;颗粒流模拟结果说明,周期荷载作用下裂隙砂岩的新的裂纹在预制裂隙尖端处集中萌生并以翼裂纹为主要扩展模式,围压作用下裂隙砂岩的破坏模式更趋向于剪切张拉复合型破坏。研究结果可为寒区裂隙岩体边坡稳定性评价及灾害防治提供参考。In order to study the deformation and failure mechanism of fractured rock mass under freeze-thaw and periodic load,the macro-meso failure mechanism of fractured sandstone under different freeze-thaw cycles was studied by combining macros-periodic load test with microscopic nuclear magnetic resonance test and numerical simulation of particle flow.The results show that the strength of fractured sandstone decreases with the increase of freeze-thaw cycles,and the expansion phenomenon increases when failure occurs,and the pore size and number increase at the meso scale.The coupling effect of freeze-thaw and degree is more serious.The microscopic performance is that the total area change rate of T_(2)peak is more obvious and the proportion of large-scale pores increases.The deformation curve trend of fractured periodic load makes the failure cracks of rock samples develop more and more complex,and the damage sandstone under cyclic loading can be used as the basis for judging the threshold range of fatigue strength and obtaining the deformation warning value.The particle flow simulation results show that under the action of periodic load,cracks are concentrated at the tip of prefabricated cracks and the wing cracks are the main propagation mode.Under the action of confining pressure,the failure mode of rock samples tends to be shear-tension composite failure.The research results can provide reference for the stability evaluation and disaster prevention of fractured rock slope in cold region.

关 键 词：冻融循环 周期荷载 裂隙砂岩 核磁共振 破坏机理 数值模拟 

分 类 号：TU452[建筑科学—岩土工程] P642[建筑科学—土工工程]