首页|冻融作用下寒区砂岩力学特性劣化规律及数值分析

冻融作用下寒区砂岩力学特性劣化规律及数值分析

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为揭示冻融岩石力学特性劣化规律,开展了寒区砂岩经不同冻融循环次数后的三轴压缩试验及数值模拟试验.结果表明:冻融次数和围压的增加导致岩石的破坏从脆性向延性转变.冻融循环次数从0次增加到40次时,岩石峰值黏聚力降低了 21.9%,内摩擦角降低了 14.7%,弹性模量的降幅都达到了 50%以上.0次冻融时,12 MPa围压时的峰值总能量较0 MPa围压时的峰值总能量增加了 670.8%,弹性能增加了 420.5%,耗散能增加了 2 356.6%;40次冻融时,峰值总能量增加了 1 030.9%,弹性能增加了 603.9%,耗散能增加了 4 153.9%.总裂纹数、拉张裂纹数、剪切裂纹数都随着轴向应变的增加展现出S形增长的特点,加载初期以剪切裂纹为主,加载至塑性阶段开始出现拉伸裂纹.研究结果可为寒区岩石力学特性劣化机理及变形破坏分析提供一定的指导.
Deterioration Law of Mechanical Properties of Sandstone in Cold-Regions Under Freeze-Thaw and Simulation Analysis
To investigate the deterioration law of rock mechanical properties under freeze-thaw,triaxial compression tests and numerical simulation experiments were conducted on sandstone specimens in cold-regions subjected to different times of freeze-thaw cycle.The results show that the increase of freeze-thaw cycles and confining pressure leads to the transformation of rock failure from brittleness to ductility.When the times of freeze-thaw cycle increased from 0 to 40,the peak cohesion of the rock decreased by 21.9%,the internal friction angle decreased by 14.7%,and the elastic modulus decreased by more than 50%.During 0 time of freeze-thaw cycle,the peak total energy at 12 MPa confining pressure increased by 670.8%compared with that at 0 MPa confining pressure,the elastic energy increased by 420.5%,and the dissipation energy increased by 2 356.6%.During 40 times of freeze-thaw cycle,the peak total energy at 12 MPa confining pressure increased by 1 030.9%compared to that at 0 MPa confining pressure,the elastic energy increased by 603.9%,and the dissipation energy increased by 4 153.9%.The total number of cracks,tensile cracks,and shear cracks under different confining pressures all exhibited an S-shaped growth pattern with the increase of axial strain,with shear cracks dominating in the early loading stage and tensile cracks appearing during the plastic stage.The research findings can provide valuable guidance for understanding the deterioration mechanism of rock mechanical properties in cold-regions and analyzing deformation and failure.

Freeze-thaw cycleCold-region sandstoneDeterioration lawEnergy evolutionBrittleness evaluation

郭威、温韬、贾文君、全志、王熠辉

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长江大学 地球科学学院,湖北 武汉 430100

湖北长大科技开发有限公司加查县分公司,西藏山南市 856499

冻融循环 寒区砂岩 劣化规律 能量演化 脆性评价

2024

矿业研究与开发
长沙矿山研究院有限责任公司 中国有色金属学会

矿业研究与开发

CSTPCD北大核心
影响因子:0.763
ISSN:1005-2763
年,卷(期):2024.44(11)