摘要
为研究云南某公路隧道上穿既有铁路隧道交叉段粉砂岩蠕变特性,利用TLW-2000三轴流变仪对现场试样进行了不同围压条件下的分级加载三轴蠕变试验。结果表明:在相同的偏应力条件下,围压越大,蠕变变形和瞬时变形越小;蠕变变形量随着载荷级数的增加呈现先减小,然后稳定,最后急剧增大的规律。另外,粉砂岩的起始蠕变速率随着围压的增大而减小。通过分析粉砂岩蠕变曲线的变化趋势,并考虑到蠕变过程中的损伤和硬化效应,采用非线性蠕变模型拟合实验数据。拟合结果表明非线性蠕变模型能够描述粉砂岩的蠕变特性。
To investigate the creep properties of siltstone in the segment from an expressway tunnel in Yunnan and on top of an existing rail tunnel,a series of tri-axial step loading creep tests were conducted on samples using TLW-2000 rock tri-axial rheometer.Results of tests indicate that the creep deformation and transient deformation decrease with the increase of confining pressure,when subjected to the identical deviatoric stress and as the steps of loading cumulates,the creep strain exhibits a trend that the creep strain increases first,stabilizes then and increases dramatically in the end.Moreover,the initial creep velocity decreases with the increase of confining pressure.Considering the damage and hardening effect during creep,a nonlinear creep constitutive model is utilized to depict the creep properties of siltstone.The fitting results show that the nonlinear creep constitutive model is competent.
出处
《桂林理工大学学报》
CAS
北大核心
2017年第3期541-546,共6页
Journal of Guilin University of Technology
基金
云南省交通科技项目[云交科教(2016)140(A)]
