防灾减灾工程学报2023，Vol.43Issue(6)：1434-1444,11.DOI:10.13409/j.cnki.jdpme.20220415001
不同应力路径下灰岩卸荷损伤特性演化规律研究
Influence of Stress Path on Unloading Mechanical Properties of Limestone
摘要
Abstract
To explore the influence mechanism of the stress path on the unloading mechanical proper-ties of limestone,we considered three unloading stress paths:unloading with a constant bias pressure unloading confining pressure,unloading with a constant axial pressure unloading confining pressure,and unloading under axial pressure andconfining pressure.This paper conducted unloading tests and numerical analyses,and analyzed the energy release law and meso-damage evolution law of limestone under different unloading stress paths.The research results show that:(1)The path of unloading stress has a significant impact on the macro-mechanical properties of limestone.Under a constant bias pressure unloading confining pressure condition,the rock sample exhibits the lowest unloading strength,and the deformation modulus and Poisson's ratio show a slower rate of change.However,it exhibits the largest range of change.Under axial pressure unloading confining pressure path,the un-loading strength is the largest.However,the variation of deformation parameters is relatively small.(2)Among the three unloading stress paths,the proportion of dissipation energy during the unloading process follows the order:constant bias pressure unloading confining pressure>constant axial pres-sure unloading confining pressure>axial pressure unloading confining pressure.The distribution of elastic strain energy is as follows:axial pressure unloading confining pressure>constant axial pressure unloading confining pressure>constant bias pressure unloading confining pressure.The findings indi-cate that the work performed by the external force is primarily converted into dissipation energy dur-ing crack development under constant bias pressure unloading confining pressure.Furthermore,the corresponding failure exhibits the highest damage variable.In contrast,when subjected to axial pres-sure unloading confining pressure,the energy is primarily converted into elastic strain energy,which is then stored within the rock sample.The failure during unloading occurs more abruptly in this case.(3)According to the numerical simulation results,under constant bias pressure unloading confining pressure,there is a higher total number of cracks and the proportion of tension cracks during the un-loading process.,Additionally,the degree of damage during unloading is the highest,with a larger value for the corresponding damage variable.In contrast,under axial pressure unloading confining pressure,the number of cracks and the damage variable of the rock sample are the smallest.Further-more,the meso-damage development law within the rock sample during the unloading process further insight into the impact of stress path on its macroscopic mechanics.关键词
卸荷/应力路径/变形特征/能量释放/细观损伤Key words
unloading/stress path/deformation characteristics/energy release/mesoscopic damage分类
建筑与水利引用本文复制引用
陈天楠,邓华锋,李建林,刘立鹏,陈兴周,李涛..不同应力路径下灰岩卸荷损伤特性演化规律研究[J].防灾减灾工程学报,2023,43(6):1434-1444,11.基金项目
国家自然科学基金项目(U2034203,51979218)、中国水利水电科学研究院水利部水工程建设与安全重点实验室开放研究基金(NO.202001)资助 （U2034203,51979218）
