摘要
盐穴储气库腔体内部压力在快速降低过程中,往往导致围岩的扩容损伤。本文通过恒轴压卸围压试验,研究了初始围压和卸载速率对盐岩卸载扩容损伤特性的影响。试验结果表明:在相同卸载速率下,初始围压越高,卸载段产生的扩容越大,与初始围压6 MPa相比,12,18 MPa时的体积应变均值分别增加7.1%和21.4%;较小的围压卸载速率对盐岩扩容有促进作用,当卸载速率从0.2 MPa/s降低到0.02,0.002,0.0002 MPa/s时,体积应变均值分别增加60.2%,103.5%,282.1%;卸载过程中扩容越大,内部损伤越严重。围压卸载段变形模量随围压的卸载逐渐减小,且初始围压和卸载速率越大,变形模量减小幅度越大。在相同应力条件下,损伤变量和围压卸载段盐岩吸收的能量随初始围压的增加而线性增加,随卸载速率的增加呈指数型降低;卸载过程中吸收能量越多,内部损伤越严重。
The rapid declination of the internal pressure in salt rock storage caverns leads to the dilatation and damage of the surround rocks.The effects of the initial confining pressure and unloading rate on the dilatation damage characteristics of salt rocks are studied in the present work,through the triaxial test with unloading confining pressure at constant axial stresses.The experimental results show that:at the same unloading rate,the higher the initial confining pressure,the larger the dilatation in the unloading stage.The mean volume strain at the confining stresses of 12 and 18 MPa increases by 7.1%and 21.4%,respectively,compared with that at the initial confining pressure of 6 MPa.Additionally,slow unloading rate of confining pressure is conductive to dilatation.As the unloading rate decreases from 0.2 MPa/s to 0.02,0.002 and 0.0002 MPa/s,the mean volume strain increases by 60.2%,103.5%and 282.1%,respectively.In the unloading process,the larger the dilatation,the more serious the internal damage.The deformation modulus in the unloading stage decreases with the unloading of confining pressure.The larger the initial confining pressure and the unloading rate,the larger the deformation modulus reduces.The damage variable and the energy absorbed by salt rock in the unloading stage increase linearly with the increase of initial confining pressure,and on the other hand,decrease exponentially with the increase of unloading rate.The more energy absorbed,the more serious the internal damage.
作者
赵德生
梁卫国
张胜利
肖宁
李静
李超
ZHAO Desheng;LIANG Weiguo;ZHANG Shengli;XIAO Ning;LI Jing;LI Chao(College of Mining Engineering,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China;Key Laboratory of Insitu Property-improving Mining of Ministry of Education,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2022年第S02期3219-3228,共10页
Chinese Journal of Rock Mechanics and Engineering
基金
国家杰出青年科学基金资助项目(51225404)
山西省自然科学基金项目(201901D211050)
关键词
岩石力学
盐穴储气库
围压卸载试验
卸载速率效应
扩容
损伤
rock mechanics
salt cavern gas storage
confined pressure unloading test
unloading rate effect
dilatation
damage
作者简介
赵德生(1995-),男,2018年毕业于太原理工大学城市地下空间工程专业,现为硕士研究生,主要从事岩石力学方面的研究工作。E-mail:zhaodeshengTYUT@163.com;通讯作者:梁卫国(1972-),男,博士,现任教授、博士生导师。E-mail:liangweiguo@tyut.edu.cn
