摘要
寒区工程中的土颗粒在重力作用下沿优势方向沉积排列而形成横观各向同性冻土材料。不考虑沉积方向与荷载方向之间沉积角的影响可能会错误估计实际工程中冻土的变形特征与承载力。然而,现有文献尚未探究沉积角对冻土工程特性的影响。针对这一问题,开展了不同温度条件下沉积角对冻土单轴压缩变形与强度特性影响的试验研究。通过所研发的制样模具制备了具有4种不同沉积角δ的冻土试样(δ=0°、30°、60°和90°),在设定的4种不同温度T条件下(T=-5、-10、-15℃和-20℃)对具有不同沉积角δ的冻土试样开展了单轴压缩试验,分析了T与δ对冻土的变形模式、破坏特征以及单轴抗压强度的显著影响。根据冻土应力-应变曲线的归一化结果及其软化段斜率的变化规律,将冻土单轴压缩变形模式在T与δ影响下分为变形模式I、II和III。根据结果可知,随着T降低以及δ趋于60°,冻土的变形模式趋于由变形模式I过渡到变形模式III,试样破坏模式由鼓胀的X形剪切带破坏趋于破坏范围较小的单剪切面破坏,而冻土单轴抗压强度随T降低而增大的同时,随δ增加表现出先减小后增大的趋势。
Soil particles in cold regions are deposited and arranged along the dominant direction due to gravity,forming transversely isotropic frozen soils.Without considering the effect of the deposition angle between the deposition direction and the load direction,the deformation characteristics and bearing capacity of the actual geotechnical engineering in cold regions may be misestimated.However,the effect of deposition angle on the mechanical properties of frozen soil has not been explored in the existing literature.In response to this problem,the uniaxial compressive tests under different temperature conditions were carried out in this paper to examine the effect of deposition angle on the mechanical behaviors of frozen soil.With the developed sample preparation mould,frozen soil samples with four different deposition anglesδ(δ=0°,30°,60°and 90°)were prepared.Uniaxial compression tests on these frozen soil samples were carried out at four different temperature conditions T(T=-5,-10,-15℃and-20℃).The significant effects of T andδon deformation mode,failure behaviors and uniaxial compressive strength of frozen soil are analyzed.The uniaxial compressive stress-strain curves of frozen soil at certain T andδare normalized,and the slope variation rule of the softened section is also analyzed.According to the above analysis,the deformation modes of the frozen soil under the effect of T andδare divided into three deformation modes,i.e.,I,II and III.According to the test results,it can be observed that as T decreases andδtends to 60°,the deformation mode of frozen soil tends to transition from deformation mode I to deformation mode III,and the failure model tends to transition from the expansion failure mode with the X-shaped shear band to the single shear plane failure mode with a smaller failure range.The uniaxial compressive strength of frozen soil increases with the decrease of T,and shows a trend of first decreasing and then increasing with the increase ofδ.
作者
梁靖宇
沈万涛
路德春
齐吉琳
LIANG Jing-yu;SHEN Wan-tao;LU De-chun;QI Ji-lin(School of Civil and Transportation Engineering,Beijing University of Civil Engineering and Architecture,Bejing 100044,China;Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education,Beijing University of Technology,Beijing 100124,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2023年第4期1065-1074,共10页
Rock and Soil Mechanics
基金
国家自然科学基金(No.52108294,No.41972279,No.52025084)
北京市博士后基金(No.2021-zz-116)
北京建筑大学市属高校基本科研业务费专项资金资助(No.X21077)。
关键词
横观各向同性
沉积角
冻土
单轴压缩试验
力学特性
transversely isotropy
deposition angle
frozen soil
uniaxial compression test
mechanical properties
