摘要
通过改进的温控三轴仪,考虑冻融围压、次数和冻结温度组合影响,对淤泥质土开展冻融后固结不排水剪切试验(FC模式)和固结后冻融不固结不排水剪切试验(CF模式),分析上述因素对淤泥质土力学特性的影响,并通过电镜扫描试验揭示冻融围压对其力学特性的影响机制。结果表明:FC模式中,冻融围压会减少冻融后土体内孔隙数量,进而降低冻融对土体强度和模量的弱化作用;而CF模式中,冻融围压使得冻融后土体内孔隙增多,土体融化时土体内超孔压增大且无消散过程,进而加剧了冻融对土体强度和模量的弱化作用;两种模式中,随着冻结温度越低和冻融次数越多,淤泥质土强度弱化效应越明显,土体破坏时的超孔隙水压力越高。淤泥质土力学指标劣化系数随冻融围压、次数和冻结温度的变化规律可用生长函数描述。
Through a self-improved temperature controlled triaxial apparatus,the consolidated undrained shear test after freeze-thaw(FC mode)and unconsolidated undrained shear test after freeze-thaw(CF mode)were carried out on the remolded muddy soil,considering the combined effects of freeze-thaw confining pressure,times and freezing temperature.The effects of the above factors on the mechanical properties of the remolded soil were analyzed.The influence mechanism of freeze-thaw confining pressure on the mechanical properties was revealed by SEM.The results show that the confining pressure during freeze-thaw cycles reduces the number of pores in the soil after freezing and thawing,thus reducing the weakening effect of freezing and thawing on the strength and modulus in FC mode.While in CF mode,the freezing and thawing confining pressure increases the pores in the soil after freezing and thawing,and the excess pore pressure in the soil increases without dissipation during the soil thawing,which further aggravates the weakening effect of freezing and thawing on the strength and modulus of the soil.In two modes,the lower the freezing temperature and the greater the number of freeze-thaw cycles,the more obvious the strength weakening effect of the muddy soil,and the higher the excess pore water pressure when the soil is yield.The variation rules of mechanical index deterioration coefficient of the muddy soil with freeze-thaw confining pressure,times and freezing temperature can be described by a growth function.
作者
张建新
马昌虎
郎瑞卿
孙立强
闫澍旺
ZHANG Jianxin;MA Changhu;LANG Ruiqing;SUN Liqiang;YAN Shuwang(Key Laboratory of Soft Soil Engineering Character and Engineering Environment of Tianjin,Tianjin Chengjian University,Tianjin 300384,China;School of Civil Engineering,Tianjin Chengjian University,Tianjin 300384,China;School of Civil Engineering,Tianjin University,Tianjin 300072,China)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2023年第S01期3801-3811,共11页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(52008286)
天津市研究生科研创新项目(2021YJSS345)
关键词
土力学
冻融围压
冻融温度
冻融次数
力学指标
劣化系数
soil mechanics
freeze-thaw confining pressure
freezing temperature
number of freeze-thaw cycles
mechanical index
deterioration coefficient
