摘要
铁路隧道建设不可避免会遇到断层、破碎带、泥化夹层、节理和裂隙等软弱结构面。软弱结构面的蠕变力学特性直接关系到隧道工程的长期稳定性。采集无扰动的天然软弱结构面立方体试样,开展不同正应力条件下的室内蠕变力学试验,以探究天然软弱结构面岩体的剪切蠕变特性,并讨论软弱结构面的长期强度的确定方法。研究结果表明:剪切蠕变过程分为瞬时阶段,瞬态蠕变阶段,稳态蠕变阶段和加速蠕变阶段;瞬时变形和蠕变变形受正应力和剪切应力的影响;稳态蠕变速率与剪应力的关系可采用指数函数或幂函数表示。软弱结构面长期强度与稳定应变率有关的确定方法操作简单,具有一定的参考意义和价值;与人工预制水泥砂浆材料的结构面岩体相比,天然软弱结构面的剪切蠕变机理更复杂,在低正应力作用下,填充的土石混合物会显著影响剪切蠕变变形。
Railway tunnel construction will inevitably encounter weak structural planes such as faults,broken zones,interlayers,joints and fissures.The rheological properties of weak structural planes are directly related to the long-term stability of tunnel engineering.In this paper,undisturbed cube samples of natural weak structural planes were collected.The indoor creep mechanics tests under different normal stress conditions were carried out to explore the shear rheological properties of rock masses with natural weak structural planes.The test results are drawn as follows.The shear creep process is divided into instantaneous phase,transient creep phase,steady-state creep phase and accelerated creep phase.Instantaneous deformation and creep deformation are affected by normal stress and shear stress.The relationship between steady-state rheological rate and shear stress can be expressed by exponential function or power law.The long-term strength of the structural plane is discussed.The determination method related to the steady-state strain rate is simple to operate and has certain reference and value.The shear creep mechanism of natural weak structural plane is significant different from the shear creep mechanism of structural planes of artificial cement mortar materials.Under low normal stress,the filled soil-rock mixture will significantly affect the shear creep deformation.
作者
陈志
贾朝军
雷明锋
CHEN Zhi;JIA Chaojun;LEI Mingfeng(China Railway 12th Bureau Group 7th Engineering Co.,Ltd.,Changsha 410075,China;School of Civil Engineering,Central South University,Changsha 410075,China)
出处
《铁道科学与工程学报》
CAS
CSCD
北大核心
2021年第7期1817-1827,共11页
Journal of Railway Science and Engineering
基金
高铁联合基金资助项目(U1934211)
湖南省自然科学基金资助项目(2020JJ5732)。
关键词
软弱结构面
剪切蠕变
蠕变速率
蠕变变形
长期强度
natural structural plane
shear creep test
shear creep rate
creep deformation
long-term strength
作者简介
通信作者:贾朝军(1989−),男,安徽天长人,讲师,博士,从事岩石力学与隧道工程研究,E−mail:jiachaojun@csu.edu.cn。
