摘要
通过开展不同加载速率下对砂岩试样的单轴压缩试验,分析了砂岩在变加载速率下的力学和能量特性。测试结果表明,砂岩的峰值强度和弹性模量随加载速率的增大呈指数函数增加。分析了砂岩在不同变形阶段的能量吸收、储存和耗散特性。在变加载速率下,砂岩的能量和轴向压缩曲线呈现类似的变化特征。砂岩在峰值前吸收总能量的70%以上可释放弹性特性的形式积累,而总能量不到30%在新微裂纹的压实、滑动和塑性阶段被各种内部缺陷消散,拟合试样峰前吸收总能量、可释放弹性能与加载速率呈线性增长关系。得到了U_(e)/U、U_(d)/U和应力比和轴向应变的关系曲线,并将其划分为3个变化阶段:原生裂隙压密闭合阶段(σ_(1)/σ_(max)<0.25)、砂岩不断吸收能量阶段(0.25<σ_(1)/σ_(max)<0.8)和能量耗散阶段(σ_(1)/σ_(max)>0.8)。加载速率越大,损伤应力和U_(e)/U也越大,而U_(d)/U越小。
Uniaxial compression tests on sandstone samples under different loading rates were conducted,and the mechanical and energy characteristics of sandstone under variable loading rates were analyzed.The test results showed that the peak strength and elastic modulus of sandstone increased as a exponential function with the increase of loading rate.The energy absorption,storage,and dissipation patterns of sandstone during different stages of deformation were analyzed.Under variable loading rates,the energy and axial compression curves of sandstone showed similar variation characteristics.More than 70%of the total energy absorbed by sandstone before peak was accumulated in the form of releasable elastic properties,while less than 30%of the total energy was dissipated by various internal defects during compaction,slip,and plastic stages of new microcrack.The fitting of the total energy absorbed before the peak and the released elastic energy of the sample showed a linear growth relationship with the loading rate.The relationship curves between U_(e)/U,U_(d)/U,stress ratio,and axial strain were obtained,and they were divided into three stages of change:the primary fracture compression closure stage(σ_(1)/σ_(max)<0.25),sandstone continuously absorbs energy stage(0.25<σ_(1)/σ_(max)<0.8)and energy dissipation stage(σ_(1)/σ_(max)>0.8).The higher the loading rate,the greater the damage stress and U_(e)/U,and the smaller the U_(d)/U.
作者
王忠伟
张迎春
温慧
娄杰
张燕斌
杨玉顺
Wang Zhongwei;Zhang Yingchun;Wen Hui;Lou Jie;Zhang Yanbin;Yang Yushun(Qipanjing Coal Mine,China Energy Mengxi Coal Chemical Industry Co.,Ltd.,Ordos 016000,China;School of Architecture and Engineering,Huaiyin Institute of Technology,Huai′an 223001,China)
出处
《能源与环保》
2024年第4期267-274,共8页
CHINA ENERGY AND ENVIRONMENTAL PROTECTION
基金
国家自然科学基金项目(51974104,51904093)
2022年度河南省重点研发与推广专项项目(222102320183)
2021年度“淮上英才计划”驻淮高校优秀博士项目。
关键词
变加载速率
单轴压缩
砂岩
力学特性
能量特性
variable loading rate
uniaxial compression
sandstone
mechanical properties
energy characteristics
