岩土力学2024，Vol.45Issue(7)：2000-2010,11.DOI:10.16285/j.rsm.2023.1335
周期性孔隙水压作用下砂岩损伤劣化特性研究
Damage and deterioration characteristics of sandstone under cyclical pore water pressure
摘要
Abstract
Due to the influence of cycle water pressure permeation,the physical and mechanical properties of sandstone in the fluctuation zone deteriorate with time,which leads to a decrease in bank slope stability.Undrained triaxial compression tests were conducted on sandstone subjected to varying cycles of pore water pressure.The evolution of the deformation,strength,and brittleness index of sandstone were investigated,and the mechanisms of microstructural deterioration were discussed.The results show that the peak stress decreases with the increase of osmotic water pressure action cycle,and the strength degradation gradually decreases with the increase of confining pressure.With an increase in the number of cycles of pore water pressure,both cohesion and internal friction angle decrease exponentially and linearly,respectively,indicating that the decrease in cohesion is the primary cause of strength deterioration.The elastic modulus,failure strain and Tarasov brittleness index decrease gradually with the increase of pore water pressure action period,however there is a significant enhancement effect with increasing confining pressure.Moreover,the failure mode has evolved from single slope shear failure to conjugate shear failure,with the fracture angle decreasing from 67.2° to 62.05°.The stress concentration and stress fatigue caused by cyclical pore water pressure at the crack tip exacerbate the internal structural degradation of sandstone.Additionally,the increase in pore water pressure during undrained compression exacerbates the damage and degradation of the sandstone,while the confining pressure causes the closure of some seepage channels,reducing the seepage damage of sandstone.关键词
库岸边坡/砂岩/应力-渗流耦合/周期性孔隙水压/脆性指数/损伤劣化Key words
reservoir slope/sandstone/stress-seepage coupling/cyclical pore water pressure/brittleness index/damage degradation分类
建筑与水利引用本文复制引用
李洪亚,马林建,刘杰,李增,邓家军,许宏发..周期性孔隙水压作用下砂岩损伤劣化特性研究[J].岩土力学,2024,45(7):2000-2010,11.基金项目
国家自然科学基金优秀青年基金(No.52222110) （No.52222110）
江苏省自然科学面上基金(No.BK20211230).This work was supported by the National Natural Science Foundation of China,Excellent Youth Program(52222110)and the Natural Science Foundation of Jiangsu Provincial(BK20211230) （No.BK20211230）
