摘要
南昌地铁部分隧道下卧地层为全风化泥质粉砂岩,在地下水和列车荷载的长期反复作用下,地层极易发生破坏,影响隧道的稳定性.对该地层岩样开展一系列循环动三轴试验,并对围压、动应力状态、荷载频率以及循环振次等参数进行研究.结果表明:施加围压可以增强岩样的结构致密性,提高岩样抵抗变形的能力,而水的渗透和初始静偏应力的施加会使岩样的结构变得松散,强度降低,并加剧其破坏程度.此外,增加动应力幅值和减小频率也会导致岩样的结构强度降低,变形程度增加.随着循环振次的增加,轴向累积应变逐渐增加,剪切模量的衰减系数逐渐减小,当循环振次超过2000时,轴向累积应变的增长幅度和剪切模量的衰减系数明显减小并逐渐趋于稳定.
The underlying strata of some tunnels in Nanchang Metro are fully weathered argillaceous,which is easy to be destroyed under the repeated action of groundwater and train load for a long time,affecting the stability of the tunnels.A series of cyclic dynamic triaxial tests are carried out on the rock samples,with parameters including confining pressure,dynamic stress state,loading frequency,and cyclic vibration frequency studied.Results indicate that applying confining pressure enhances the structural compactness of the rock sample,improving its resistance to deformation.Conversely,water permeation and the application of initial static deviatoric stress cause the rock structure to loosen,reducing strength and accelerating failure.Additionally,increasing dynamic stress amplitude and decreasing frequency also diminish structural strength and increase deformation.As the cyclic vibration frequency increases,the axial cumulative strain gradually increases,and the decay coefficient of the shear modulus gradually decreases.When the cyclic vibration frequency exceeds 2000,the growth rate of axial cumulative strain and the decay variation of shear modulus significantly decrease and gradually stabilize.
作者
石钰锋
罗干
王超
王陈君
李永平
SHI Yufeng;LUO Gan;WANG Chao;WANG Chenjun;LI Yongping(School of Civil Engineering and Architecture,East China Jiaotong University,Nanchang 330013,China;Jiangxi Architectural Design Institute Co.,Ltd.,East China Jiaotong University,Nanchang 330013,China;China Railway 24th Bureau Group Co.,Ltd.,Shanghai 200071,China)
出处
《湖南科技大学学报(自然科学版)》
北大核心
2025年第5期29-35,共7页
Journal of Hunan University of Science And Technology:Natural Science Edition
基金
国家自然科学基金面上项目资助(42177162)
国家自然科学基金地区科学基金资助项目(52368053)。
关键词
循环荷载
盾构隧道
全风化泥质粉砂岩
动力特性
cyclic load
shield tunnel
fully weathered argillaceous siltstone
dynamic characteristic
