不同加载速率下冻融砂岩的动态劈裂特性  

Dynamic Splitting Characteristics of Freeze-Thawed Sandstone at Different Loading Rates

作　　者：贾蓬[1] 毛松泽 钱一锦 卢佳亮 JIA Peng;MAO Song-ze;QIAN Yi-jin;LU Jia-iang(School of Resources&Civil Engineering,Northeastern University,Shenyang 110819,China)

机构地区：[1]东北大学资源与土木工程学院,辽宁沈阳110819

出　　处：《东北大学学报（自然科学版）》2024年第1期111-119,共9页Journal of Northeastern University(Natural Science)

基　　金：国家重点研发计划项目(2022YFC2903903);国家自然科学基金资助项目(52174071).

摘　　要：为研究加载速率和冻融循环对砂岩动态劈裂特性的影响,对冻融0,25,50,75,100次的砂岩进行了静态和不同加载速率的动态劈裂试验,分析了冻融砂岩的静动态抗拉强度及冲击荷载作用下耗散能变化规律.研究结果表明:冻融砂岩的静动态抗拉强度、纵波波速、质量损失率均随冻融次数增加而劣化.随冻融次数、加载速率增加,动强度增加因子(DIF)不断增大,且砂岩冻融损伤越大,DIF随加载速率增加越明显.建立的基于冻融损伤和加载速率的动态抗拉强度预测模型可以很好地反映砂岩的强度变化.砂岩的冻融损伤越大,动态抗拉强度随加载速率的变化速率越快;冲击荷载作用下的耗散能随冻融次数增加而减小,随加载速率增加而增大.In order to study the effects of loading rate and freeze-thaw cycles on the dynamic splitting characteristics of sandstone,static and dynamic splitting tests with different loading rates were conducted on sandstone subjected to 0,25,50,75 and 100 freeze-thaw cycles,and the static and dynamic tensile strength of freeze-thaw sandstone,as well as the change law of dissipation energy under impact load were discussed.The results show that the static and dynamic tensile strength,the P-wave velocity and the mass loss rate of freeze-thaw sandstone deteriorate with an increase in the number of freeze-thaws cycles.The dynamic strength increase factor(DIF)increases with the increase of freeze-thaw cycles and loading rate,and a higher degree of the freeze-thawing damage in sandstone results in a more significant increase in DIF with loading rate.The dynamic tensile strength prediction model based on freeze-thaw damage and loading rate can reflect the strength change of sandstone effectively.The greater the freeze-thaw damage of sandstone,the faster the change of dynamic tensile strength with loading rate.The dissipation energy under impact load decreases with the increase of freeze-thaw cycles and increases with higher loading rate.

关 键 词：冻融循环 加载速率 损伤 动态抗拉强度 能量耗散 

分 类 号：TU452[建筑科学—岩土工程]