摘要
【目的】为探究寒区冻融损伤与开挖卸荷损伤对岩体力学特性的影响,【方法】对砂岩开展了考虑卸荷与冻融损伤两个损伤因素以不同作用顺序下的室内力学试验,分析砂岩力学特性及能量演化规律。【结果】结果显示:岩样单轴抗压强度与弹性模量均在“卸荷-冻融”条件劣化最大,破裂形态随循环次数增大由剪切破坏逐渐向拉剪复合破坏演化且主破坏面及张拉裂纹易沿宏观冻融裂纹发展;损伤劣化使岩样耗散能及其占比增大,储能极限减小。【结论】结果表明:岩样冻融时的初始孔隙状态对劣化程度有较大影响,前期冻融损伤对卸荷损伤的反馈程度要低于前期卸荷损伤对冻融损伤的反馈程度;卸荷与冻融对岩样的损伤机制对岩样破坏形态、耗散能占比及弹性能储存释放有直接影响。
[Objective]To investigate the effects of freeze-thaw damage and excavation unloading damage on the mechanical properties of rock masses in cold regions.[Methods]Indoor mechanical tests were conducted on sandstone considering unloading and freeze-thaw damage factors in different order of action,and the mechanical properties and energy evolution laws of sandstone were analyzed.[Results]The result showed that the degradation of uniaxial compressive strength and elastic modulus of rock samples is most significant under the condition of“unloading freeze-thaw”.The fracture morphology gradually evolves from shear failure to tensile shear composite failure with increasing cycle times,and the main failure surface and tensile cracks are prone to develop along macroscopic freeze-thaw cracks.Damage increases the dissipated energy and its proportion during the process of rock sample failure,while reducing the energy storage limit.[Conclusion]The initial pore state of rock samples during freeze-thaw has a significant impact on the degree of degradation,and the feedback degree of early freeze-thaw damage to unloading damage is lower than that of early unloading damage to freeze-thaw damage.The damage mechanism of unloading and freeze-thaw on rock samples has a direct impact on the fracture morphology,proportion of dissipated energy,and storage and release of elastic energy of rock samples.
作者
苏振坤
刘平
张峰华
陈莉丽
龚盛
陈兴周
李针汗
SU Zhenkun;LIU Ping;ZHANG Fenghua;CHEN Lili;GONG Sheng;CHEN Xingzhou;LI Zhenhan(Architecture and Civil Engineering College,Xi’an University of Science and Technology,Xi’an 710054,Shaanxi,China;Engineering Construction Branch,Qinghai Yellow River Upstream Hydropower Development Co.,Ltd.,Xining 810003,Qinghai,China)
出处
《水利水电技术(中英文)》
北大核心
2025年第5期240-253,共14页
Water Resources and Hydropower Engineering
基金
国家自然科学基金项目(51979218)。
关键词
砂岩
卸荷损伤
冻融损伤
力学特性
能量演化
影响因素
抗压强度
sandstone
unloading damage
freeze-thaw damage
mechanical properties
energy evolution
influenaing factors
compressive strength
作者简介
苏振坤(1999-),男,硕士研究生,主要从事水工岩体力学方面的研究。E-mail:zksu1022@163.com;通信作者:陈兴周(1980-),男,教授,博士研究生导师,博士,主要从事水工岩体力学及工程渗流方面的研究。E-mail:xzchen0416@163.com。
