摘要
泥化夹层是诱发岩体工程失稳破坏的重要因素之一。为研究循环动荷载下泥化夹层的累积变形特性,深入分析主要影响因素,在黄河中游某大型水利枢纽工程勘探平硐采取试样,开展了不同工况条件下泥化夹层的动三轴试验研究。在考虑主要黏土矿物成分、黏粒含量、含水率、围压和频率等影响因素的基础上,根据试验成果,探求适合描述泥化夹层累积应变发展规律的理论模型,并基于动应力~应变关系研究了泥化夹层的动弹性模量特征。研究结果表明:(1)泥化夹层的累积应变发展规律具有破坏型特征,不符合稳定型累积应变特征,利用Monismith模型进行描述是合理的;(2)泥化夹层的动应力~应变曲线符合Hardin双曲线模型;(3)泥化夹层的累积应变随含水率、黏粒含量和频率的增大而增大,随围压的增大先减小后增大;(4)泥化夹层的动弹性模量随围压增大单调递增,随循环周次、含水率和频率的增大而单调递减;(5)主要黏土矿物成分为蒙伊混层时,泥化夹层的累积应变最大,动弹性模量随循环周次增加而衰减最快。
The mudded intercalations are known to deteriorate engineering properties of layered rock mass.This paper aimed to experimentally reveal the accumulative deformation characteristics and analyze the impact factors of mudded intercalations under cyclic dynamic loading.The specimens of mudded intercalations were collected from an exploration adit of some large-scale water control project in the middle reaches of Yellow River.They were remolded and prepared for dynamic triaxial test under cyclic loading.Some key impact factors,i.e.main clay mineral composition,clay content,moisture content,confining pressure and frequency were considered during dynamic triaxial tests with different conditions.A theoretical model was put forward for the cumulative strain description of mudded intercalations according to the test results.The variation laws of dynamic elastic modulus with cyclic numbers were discussed based on the dynamic stress-strain curves.The results show that the cumulative strain development law of mudded intercalations has failure characteristics,which doesn't meet the stable cumulative strain characteristics.It is reasonable to describe the characteristics of cumulative strain by the Monismith model.The dynamic stress-strain curves accord with the Hardin hyperbolic model.The key impact factors have great effects on the cumulative strain,such as cyclic numbers(positive),moisture content(positive),clay content(positive),frequency(positive),and confining pressure(negative).The dynamic elastic modulus is impacted by confining pressure(monotonously positive),cyclic numbers(monotonously negative),moisture content and frequency(monotonously negative).When the main mineral composition is mixed montmorillonite and illite,the cumulative strain of mudded intercalations reaches its maximum,and the dynamic elastic modulus decrease fastest.
作者
闫长斌
徐晓
姜晓迪
张晓英
陈书丽
YAN Changbin;XU Xiao;JIANG Xiaodi;ZHANG Xiaoying;CHEN Shuli(School of Civil Engineering,Zhengzhou University,Zhengzhou 450001,China;Yellow River Engineering Consulting Co.,Ltd.,Zhengzhou 450003,China)
出处
《振动与冲击》
EI
CSCD
北大核心
2020年第11期280-287,共8页
Journal of Vibration and Shock
基金
国家自然科学基金(41972270)
河南省重点研发与推广专项(182102210014)
郑州大学青年骨干教师培养计划项目。
关键词
泥化夹层
动三轴试验
累积应变模型
动弹性模量
影响因素
mudded intercalations
dynamic triaxial tests
cumulative strain models
dynamic elastic modulus
impact factors
