摘要
盐渍冻土与混凝土接触界面的力学特性对寒旱区道路工程结构的稳定性和耐久性有重要的影响。为了揭示多因素作用下盐渍冻土-混凝土接触面力学特性,通过室内试验和数学模型探究了接触面剪切应力-位移关系和剪切强度变化规律。开展了补水和不补水、冻融循环方式(单向和整体冻融循环)、冻融循环次数(0次、5次、10次、20次)、含盐量(0、0.5%、1%、2%、3%、4%)、含盐类型(NaCl和Na_(2)SO_(4))、剪切温度(-2℃、-5℃、-10℃)等条件下的盐渍冻土-混凝土接触面直剪试验。基于龚帕兹模型拟合了接触面的剪应力-剪切位移关系。并运用灰色相关理论分析了各影响因素与接触面剪切强度关联性。研究结果表明:冻融循环方式对接触面抗剪强度的影响差异不明显,但随着冻融循环次数增加,接触面抗剪强度均逐渐降低。接触面抗剪强度随着盐含量的增加而降低,当含盐量超过2%时,硫酸钠和氯化钠冻土接触面抗剪强度呈现相反变化规律,其中硫酸钠冻土接触面强度增大。当温度降至-5℃及更低温度后,补水条件对接触面抗剪强度起增强作用。龚帕兹模型与盐渍冻土-混凝土接触面的应力位移关系吻合较好,可用于评价寒旱盐渍土区土-混凝土接触面剪切特性。由灰色关联分析得出各影响因素的显著性排序为:含水率>剪切温度>冻融循环次数>氯化钠含盐量>硫酸钠含盐量。
The mechanical properties of the interface between saline frozen soil and concrete have an important impact on the stability and durability of road engineering structures in cold and dry areas.In order to reveal the mechanical characteristics of the contact surface between saline frozen soil and concrete under the action of multiple factors,the shear stress-displacement relationship and shear strength of the contact surface were studied through laboratory tests and mathematical models.Firstly,the direct shear test of saline frozen soil-concrete interface was carried out under the conditions of water supplement and no water supplement,freeze-thaw cycle mode(one-way freeze-thaw cycle and overall freeze-thaw cycle),freeze-thaw cycle number(0,5,10,20),salt content(0,0.5%,1%,2%,3%,4%),salt content type(NaCl and Na_(2)SO_(4)),shear temperature(-2℃,-5℃,-10℃),etc.Secondly,the relationship between shear stress and shear displacement of the contact surface is fitted based on the Gomez model,and the applicability of the model is evaluated.Finally,the grey correlation theory is used to analyze the correlation between each influencing factor and the shear strength of the contact surface,and the significance ranking of each influencing factor is established.The results show that the influence of freeze-thaw cycles on the shear strength of the contact surface is not obvious,but as the number of freeze-thaw cycles increases,the shear strength of the contact surface gradually decreases.The shear strength of the contact surface decreases with the increase of salt content.When the salt content exceeds 2%,the shear strength of the contact surface of sodium sulfate and sodium chloride frozen soil presents an opposite change rule,and the strength of the contact surface of sodium sulfate frozen soil increases.When the temperature drops to-5℃or lower,the water supplement condition enhances the shear strength of the contact surface.The Gompaz model is in good agreement with the stress-displacement relationship of the interface between saline frozen soil and concrete,and can be used to evaluate the shear characteristics of the soil-concrete interface in the cold and dry saline soil area.According to the grey correlation analysis,the order of significance of each influencing factor is:moisture content>shear temperature>freeze-thaw cycles>sodium chloride salt content>sodium sulfate salt content.
作者
万旭升
周浩
路建国
晏忠瑞
刘凤云
杨乾承
WAN Xusheng;ZHOU Hao;LU Jianguo;YAN Zhongrui;LIU Fengyun;YANG Qiancheng(School of Civil Engineering and Surveying and Geomatics,Southwest Petroleum University,Chengdu 610500,China)
出处
《工程地质学报》
北大核心
2025年第4期1553-1565,共13页
Journal of Engineering Geology
基金
国家自然科学基金项目(资助号:42271146,42071087,42101136)
四川省自然科学基金项目(资助号:2022NSFSC0438)。
关键词
道路工程
盐渍土
直剪试验
接触面
冻融循环
Road engineering
Saline soil
Direct shear test
Interface
Freeze-thaw cycle
作者简介
第一作者/通讯作者:万旭升(1987-),男,博士后,教授,博士生导师,主要从事盐胀机理及寒区工程研究.E-mail:wanxs@swpu.edu.cn。
