干湿循环对路基改良土加州承载比与回弹模量的研究  

Research on CBR and Springback Modulus of Improved Roadbed Soil by Drying-Wetting Cycles

作　　者：崔宏环 朱超杰 张立群 胡淑旗 CUI Honghuan;ZHU Chaojie;ZHANG Liqun;HU Shuqi(Hebei Provincial Key Laboratory of Civil Engineering Diagnosis,Reconstruction and Disaster Resistance,Zhangjiakou 075000,China;Civil Engineering College,Hebei University of Architecture,Zhangjiakou 075000,China)

机构地区：[1]河北省土木工程诊断、改造与抗灾实验室,河北张家口075000 [2]河北建筑工程学院土木工程学院,河北张家口075000

出　　处：《森林工程》2023年第1期187-196,共10页Forest Engineering

基　　金：国家自然科学基金项目(51878242);河北省教育厅重点项目(ZD2020325);张家口市应用基础研究专项项目(1911032A)。

摘　　要：为解决雨水交换对路基损坏度量指标,通过模拟雨水频繁气候地区水汽交换对公路路基的影响,采用室内力学试验研究干湿循环对冀北地区高等级公路路基改良土的影响。研究结果表明,28 d养护龄期的水泥改良土经历干湿循环后加州承载比(California Bearing Ratio, CBR)值与回弹模量满足指数函数关系;90 d养护龄期的水泥改良土干湿损伤最为明显、28 d次之,早期水泥水化作用可以修复干湿循环所造成的损伤。通过微观对比得出28 d养护龄期的改良土试样随着干湿循环次数的增加骨架面积先增大后减小,骨架排列方式也随之改变。因此,建议7 d养护龄期CBR值以370%,28 d养护龄期以500%作为参考。综合无侧限抗压强度、回弹模量及CBR值各项指标,建议在水汽交换频繁地区路基改良中以6%水泥掺量作为参考。In order to solve the damage index of roadbed caused by rain exchange, by simulating the influence of water vapor exchange on highway subgrade in the climate area with frequent rainfall, the influence of drying-wetting cycles on modified soil of highway subgrade in northern Hebei was studied by indoor mechanical test. The results showed that the California Bearing Ratio(CBR) value and springback modulus of cement-modified soil at 28 days of curing met the exponential function relationship after the drying-wetting cycles. The dry-wet damage of cement-modified soil at 90 days of curing was the most obvious, followed by 28 days, and the early cement hydration can repair the damage caused by the drying-wetting cycles. Through microscopic comparison, it can be concluded that the skeleton area of modified soil samples with 28 d curing age increased first and then decreased with the increase of the number of drying-wetting cycles, and the skeleton arrangement also changed. According to the results of this study, it was recommended that the CBR(California Bearing Ratio) value of 7 d curing age should be 370% and that of 28 d curing age should be 500% as reference. Based on the unconfined compressive strength, springback modulus and CBR indexes, it was suggested that 6% cement content should be used as a reference for roadbed improvement in areas with frequent water vapor exchange.

关 键 词：水泥改良土 干湿循环 加州承载比(CBR) 回弹模量 微观分析 

分 类 号：U416.111[交通运输工程—道路与铁道工程]