有压冻融循环对冻结黄土强度特性影响  

The Influence on Strength Characteristics of Frozen Loess under Pressure Freeze-thaw Cycle

作　　者：黄素素 雷乐乐 郭旭 张志成 罗祥 王振华[1] HUANG Susu;LEI Lele;GUO Xu;ZHANG Zhicheng;LUO Xiang;WANG Zhenhua(School of Civil&Architecture Engineering,East China University of Technology,Nanchang 330013,China)

机构地区：[1]东华理工大学土木与建筑工程学院,南昌330013

出　　处：《森林工程》2024年第5期181-189,共9页Forest Engineering

基　　金：江西省教育厅科学技术研究项目(GJJ2200773);江西省自然科学基金青年基金项目(20232BAB214097);国家自然科学基金项目(42061011);江西省自然科学基金重点研发计划项目(20223BBG71W01)。

摘　　要：为进一步探究实际工况下冻融对黄土变形和强度的影响,开展经历0、1、4次有压冻融循环后的黄土压缩试验。结果表明,经历有压冻融后,冻结黄土多呈现脆性破坏模式,应力-应变曲线表现为应变硬化型曲线;经历1次有压冻融循环的黄土强度降低约35%,经历4次有压冻融循环的黄土强度降低近51%,二者呈非线性负相关关系;相同冻融循环次数情况下,随着含水率的增加,峰值应力会逐渐减小,试验含水率范围内强度降低近77%;冻结黄土单轴抗压强度会随初始干密度的增加及试验温度的降低而呈现显著增大的趋势,当温度从-10℃降低至-15℃,强度增大1.5倍,从-15℃降低至-20℃,强度增大近2倍;最后基于高斯函数,构建有压冻融循环影响的冻结黄土强度模型,使其能较好地反映冻结黄土的应变硬化情况。In order to further explore the influence of freezing and thawing on the deformation and strength of loess under the actual working conditions,this paper carries out the compression test of loess after experiencing 0,1,and 4 pressurized freeze-thaw cycles,respectively.The results show that:after experiencing pressurized freeze-thaw,the frozen loess mostly shows brittle damage mode,and the stress-strain curve is strain-hardening curve.The strength of loess decreases by about 35%after one pressurized freezethaw cycle,and the strength decreases by 51%after four pressurized freeze-thaw cycles,which is a nonlinear negative correlation.In the case of the same number of freeze-thaw cycles,with the increase of the water content,the peak stress will be reduced gradually and the strength in the range of water content decreases by nearly 77%.The uniaxial compressive strength of frozen loess shows a significant increase with the increase of initial dry density and the decrease of test temperature,when the temperature decreases from-10℃to-15℃,the strength increases 1.5 times,and the strength increases 2 times when the temperature decreases from-15℃to-20℃.Finally,based on the Gaussian function,a strength model of frozen loess is constructed considering the influence of pressurized freeze-thaw cycles,which can better reflect the strain hardening situation of frozen loess.

关 键 词：冻结黄土 抗压强度 压缩试验 有压冻融循环 强度模型 

分 类 号：U213.14[交通运输工程—道路与铁道工程]