Effect of water saturation on dynamic behavior of sandstone after wetting-drying cycle treatment
Effect of water saturation on dynamic behavior of sandstone after wetting-drying cycle treatment
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DOI：
10.1016/j.enggeo.2023.107105
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发表时间：
2023-03
影响因子：
7.4
通讯作者：
Hongru Li;Yafei Qiao;M. He;Rongxi Shen;Zhoujie Gu;Tai Cheng;Ying-chao Xiao;Jie Tang
中科院分区：
文献类型：
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作者：
Hongru Li;Yafei Qiao;M. He;Rongxi Shen;Zhoujie Gu;Tai Cheng;Ying-chao Xiao;Jie Tang
充分认识水对岩石材料力学性能的影响，对岩石工程的安全设计和评价具有重要意义。采用低场核磁共振（LF-NMR）和扫描电子显微镜（SEM）等方法对砂岩进行了不同干湿循环次数（0-15）的预处理，并对其孔隙特征进行了表征。在此基础上，分别在干态和饱和态下进行了相同撞击速度的分离式霍普金森压杆（SHPB）实验。重点讨论了不同孔隙度条件下含水饱和度对砂岩动态特性的影响及其机理。结果表明，随着循环次数的增加，砂岩的孔隙率增大，动强度和总耗能降低。峰后能量耗散所占比例增加，破碎化程度加剧。随着孔隙度的增加，含水饱和度对动强度的影响由增强到减弱。这可能与Stefan效应与孔隙水压力贡献之间的竞争有关。最后，建立了考虑干湿循环与动荷载耦合作用的动损伤本构模型，并验证了模型的有效性。
Fully understanding the influence of water on the rock materials' mechanical properties is of great significance to the safety design and evaluation in rock engineering. In this study, sandstone was pretreated with different wetting-drying cycles (0-15), and its pore characteristics were characterized by low-field nuclear magnetic resonance (LF-NMR) and scanning electron microscope (SEM) methods. Then, the split Hopkinson pressure bar (SHPB) tests with the same impact velocity were carried out in its dry and saturated states, respectively. The effects of water saturation on the dynamic behavior of sandstone under different porosity conditions and their mechanisms were emphasized. The results show that with the increase of cycle numbers, the porosity of sandstone increases, the dynamic strength and the total energy dissipation decreases. Moreover, the proportion of post-peak energy dissipation rises, and the degree of fragmentation intensifies. With the increase of porosity, the effect of water saturation on dynamic strength changes from enhancement to weakening. This may be related to the competition between the the Stefan effect and the contribution of pore water pressure. Finally, a dynamic damage constitutive model considering the coupling effect of the wetting-drying cycles and dynamic loads was established, and its effectiveness was verified.