土木与环境工程学报（中英文）2024，Vol.46Issue(6)：1-8,8.DOI:10.11835/j.issn.2096-6717.2022.091
分级循环卸-加围压下粉砂岩的力学特征
Mechanical characteristics of siltstone under staged cyclic unloading-loading confining pressure
摘要
Abstract
For engineering practice,conducting experiments with different stress paths to study the mechanical characteristics of rock masses is essential.In order to study the mechanical characteristics of siltstone under the special stress path of cyclic unloading-loading of confining pressure,the MTS815 rock mechanics testing system was used to conduct staged cyclic unloading-loading confining pressure tests at different axial force levels,and the evolution characteristics of axial and circumferential plastic strain and elastic modulus at different stress levels were analyzed.The relationship between the energy evolution and the deformation as well as the damage of the specimens was also analyzed via calculation of dissipated energy.The results show that the hysteresis loops move in the direction of strain increase as the number of cycles increases,and the stress-strain curves of unloading-loading confining pressure gradually close,and the overall change of hysteresis loop spacing is from"sparse"to"dense".The lower the unloading level is,the lower the modulus of elasticity is,while the lower the stress level is,the higher the modulus of elasticity is.Modulus of elasticity is affected by both the axial force level and the unloading level;the circumferential plastic strain is generally larger than the axial value in a single cycle,and the resistance to plastic deformation at high axial force levels is stronger than that at low force levels under the special stress path;the total energy dissipated in the final damage of the rock is positively correlated with the axial force level to some extent.关键词
粉砂岩/循环卸-加围压/塑性应变/耗散能量/岩石力学/应力路径Key words
siltstone/cyclic unloading-loading confining pressure/plastic strain/dissipation energy/rock mechanics/stress paths分类
建筑与水利引用本文复制引用
苗胜军,段懿轩,刘春康,卢新爱..分级循环卸-加围压下粉砂岩的力学特征[J].土木与环境工程学报（中英文）,2024,46(6):1-8,8.基金项目
国家自然科学基金(51974014、51574014)National Natural Science Foundation of China(Nos.51974014,51574014) （51974014、51574014）
