摘要
地下硐室开挖后,卸荷条件下围岩蠕变现象显著,以某深埋矿井巷道顶板页岩为研究对象,开展恒轴压卸围压蠕变实验,分析页岩卸荷蠕变的非线性特征,构建一种新的描述页岩卸荷蠕变行为的非线性模型。研究表明:在恒轴压卸围压条件下页岩蠕变特征显著,轴向和侧向蠕变曲线形态较为相似,轴向应变值总体上大于侧向;页岩轴向蠕变速率曲线存在一个初始蠕变速率值,较短时间内逐渐衰减,稳定蠕变阶段中蠕变速率基本恒定,最后一级卸载呈加速蠕变;页岩在卸荷蠕变过程中的长期强度仅为瞬时强度的61.05%,长期强度折减较大。该研究为页岩卸荷蠕变特性及地下工程围岩稳定性研究提供一定参考。
This paper aims to address the significant creep phenomenon of the surrounding rocks under the unloading condition following the excavation of the underground chamber.The study involves performing the constant axial pressure unloading confining pressure creep experiment by taking the roof shale of a deep buried mine roadway as the research object;analyzing the nonlinear characteristics underlying shale unloading creep;and developing a new nonlinear model capable of accurately describing the unloading creep behavior of shale.The results show that shales subjected to constant axial pressure and unloading confining pressure present the significant creep characteristics,with the axial and lateral creep curves being of a relatively similar shape and the axial strain being of a generally greater value than lateral strain;an initial creep rate value exists in the axial creep rate curve of shale,showing gradual decays in a shorter time,and staying basically constant in the stable creep stage,and exhibiting an accelerated creep with sharp increase of creep rate in the last unloading stage;the shale is of long-term strength during unloading creep,which is only 61.05%of the instantaneous strength,with the greatly reduced long-term strength.The research could inform the study of shale unloading creep characteristics and surrounding rock stability of underground engineering.
作者
蒋仕荣
虞子楠
Jiang Shirong;Yu Zinan(Guangxi Dahan Geotechnical Engineering Co. Ltd., Guiling 541001, China;College of Highway, Chang′an University, Xi′an 710064, China)
出处
《黑龙江科技大学学报》
2021年第5期585-590,共6页
Journal of Heilongjiang University of Science And Technology
基金
国家重点基础研究发展计划“973计划”项目(2017YFD0800501)。
关键词
页岩
卸荷蠕变
蠕变速率
长期强度
非线性
shale
unloading creep
creep rate
long term strength
nonlinearity
