冻融循环作用下伊犁盐渍化黄土力学特性
Mechanical properties of Ili salinized loess under freeze-thaw conditions
包卫星 1吴倩 1吴谦 1秦川 1侯天琪1
作者信息
- 1. 长安大学公路学院,陕西西安 710064
- 折叠
摘要
为研究冻融循环次数、围压和含盐量等因素对伊犁盐渍化黄土力学特性的影响,开展室内冻融循环作用下含盐黄土的三轴试验,分析盐渍化黄土在冻融和盐蚀作用后的劣化机制,提出盐渍化黄土的强度劣化公式和本构模型.结果表明:在冻融循环作用下,盐分的增多使应力-应变曲线由软化型转向硬化型;当含盐量较高时,黄土的抗剪强度随着冻融循环次数的增多迅速衰减.黏聚力与冻融循环次数呈指数关系;内摩擦角随冻融循环次数的增加先增大后减小、随含盐量的增大而减小.建立冻融作用下黏聚力的劣化模型,该模型能预测不同含盐量试件的黏聚力劣化特性;冻融作用对黏聚力衰减的权重大于盐蚀作用.提出考虑多因素作用下修正的Duncan-Chang模型,该模型能更准确地反映冻融和盐蚀作用后盐渍化黄土的强度和变形特性.
Abstract
In order to study the influence of factors such as the number of freeze-thaw cycles,confining pressure,and salt content on the mechanical properties of salinized loess in Ili,triaxial tests of salinized loess under the action of indoor freeze-thaw cycles were carried out.The deterioration mechanism of salinized loess after freeze-thaw and salt erosion was analyzed,and the strength deterioration formula and constitutive model of salinized loess were proposed.The results show that the increase of salt makes the stress-strain curve shift from softening type to hardening type under the action of freeze-thaw cycles.When the salt content is higher,the shear strength of loess decreases rapidly with the increase of the number of freeze-thaw cycles.The cohesion is exponentially related to the number of freeze-thaw cycles.The internal friction angle shows an increase and then a decrease with the increase in the number of freeze-thaw cycles and decreases with the increase in salt content.A degradation model of cohesion under freeze-thaw is established,which can predict the degradation characteristics of cohesion in specimens with different salt contents.The weight of the freeze-thaw effect on cohesion degradation is greater than that of salt corrosion.A modified Duncan-Chang model with multi-factors is proposed,which can more accurately reflect the strength and deformation characteristics of salinized loess after freeze-thaw and salt erosion.
关键词
土力学/含盐量/应力-应变/劣化模型/Duncan-Chang模型Key words
soil mechanics/salt content/stress-strain/deterioration model/Duncan-Chang model引用本文复制引用
基金项目
国家自然科学基金资助项目(52308435)
新疆维吾尔自治区重大科技专项项目(2020A03003-7)
陕西省自然科学基础研究计划(2021JM-180)
出版年
2024
NETL
NSTL
万方数据