摘要
为探究浅季节性冻土区不同密实状态的下膨胀土力学特性随冻融周期作用的演化规律,以取自平顶山的弱~中膨胀土为研究对象,配制不同密实状态的膨胀土试样,采用气候边缘地带浅季冻区极端低气温为冻结温度进行冻融循环与三轴剪切试验。试验结果表明:冻融循环作用下不同密实状态膨胀土的弹性模量、破坏强度及黏聚力均发生较大幅度衰减,内摩擦角则随冻融次数增加而呈现出波动性缓慢增长趋势;高压实系数膨胀土的“弱软化型”主应力差-应变关系随着围压和冻融次数增加而逐渐转变为“弱硬化型”;低压实系数膨胀土主应力差-应变关系为“硬化型”且随着围压增加而增强;相同密实状态与侧向约束围压时,膨胀土达到相同应变时的主应力差随冻融次数增加而迅速减小。
To explore the evolution of mechanical properties of expansive soil under different compaction states in seasonal frozen soil areas with the action of freezing-thawing cycles,based on the expansive soil in Pingdingshan region of Henan province,expansive soil samples with different compaction states were prepared.Freezing-thawing cycles and triaxial shear tests were conducted using the extreme low temperature of the seasonal frozen zone as the freezing temperature.The experimental results show that the failure strength,elastic modulus and cohesion of expansive soil decrease under the action of freezing-thawing cycles,while the internal friction angle increases slowly with the increase of freezing-thawing cycles.With the increase of confining pressure and freeze-thaw times,the“weak softening”stress-strain relationship of expansive soil with high compaction coefficient gradually changes to“weak hardening”.The stress-strain relationship of expansive soil with low-compaction coefficient is“hardening type”and increases with the increase of confining pressure.The principal stress difference of expansive soil under the same compaction state and lateral confining pressure decreases rapidly with the increase of freezing-thawing times.
作者
王亮亮
王照腾
田建胜
林宇亮
于明晖
WANG Liangliang;WANG Zhaoteng;TIAN Jiansheng;LIN Yuliang;YU Minghui(State Key Laboratory for Geomechanics&Deep Underground Engineering,China University of Mining and Technology,Xuzhou 221116,China;School of Mechanics and Civil Engineering,China University of Mining and Technology,Xuzhou 221116,China;School of Civil Engineering,Central South University,Changsha 410075,China)
出处
《铁道学报》
EI
CAS
CSCD
北大核心
2023年第11期146-153,共8页
Journal of the China Railway Society
基金
中国博士后科学基金(2016M591957)。
关键词
膨胀土
压实系数
冻融循环
力学特性
演化规律
expansive soil
compaction coefficient
freeze-thaw cycles
mechanical property
evolution law
