摘要
通过模拟雨水频繁气候地区水汽交换对公路路基的影响,利用室内力学试验研究干湿循环对张家口地区高等级公路路基改良土的影响,得到了各力学参数的变化规律,并提出采用水泥CBR影响因子来评判水泥改良土路用性能的劣化机理。水泥CBR影响因子反映的是相同水泥掺量下试样的承载强度和水泥对工程应用的贡献程度,其值越大说明试样在相同水泥掺量下的承载强度越小,对于工程应用的贡献越小。研究结果表明:水泥CBR影响因子受水泥掺量的影响较大,随着干湿循环次数的增加,水泥CBR影响因子先减小后增大;高剂量的水泥改良土可以有效地提高土样的自修复能力,在早期抵抗干湿损伤中具有积极作用,弹性模量受干湿循环影响较小。试样内部孔隙特征变化规律显示,早期干湿循环过程可增强改良土的水稳定性,经历多次干湿循环后试样内部孔隙逐渐扩大—破坏—稳定,重新达到新的结构平衡。综合考虑CBR值与无侧限抗压强度,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。
By simulating the impact of water vapor exchange on highway subgrades in areas with frequent rains,this paper studied the impact of drying-wetting cycles on the improved soil of high-grade highway subgrades in Zhangjiakou area with indoor mechanical tests.It obtained the change law of various mechanical parameters,and put forward the cement CBR influence factor to judge the degradation mechanism of cement-improved soil road perfor-mance.The cement CBR influence factor reflects the load-bearing strength of the sample under the same cement content and the contribution of the cement to the project.The larger the CBR influence factor,the smaller the bearing strength of the sample under the same cement content,and the smaller the contribution value to engineering applications.The results show that the impact factor of cement CBR is greatly affected by the amount of cement.As the number of drying-wetting cycles increases,the impact factor of cement CBR first decreases and then increases.The high-dose cement-modified soil can effectively improve the self-healing ability of the soil sample,and has a positive effect in the early resistance to drying-wetting damage,and the elastic modulus is less affected by the drying-wetting cycle.The change law of the internal pore characteristics of the sample indicates that the early drying-wetting cycle process can enhance the water stability of the modified soil.After multiple drying-wetting cycles,the internal pores of the sample are expanded,destroyed and stabilized gradually,and reached a new structural balance again.According to the comprehensive analysis of CBR technical indicators and unconfined compressive strength indicators,it is recommended to use 6%cement as a reference for subgrade improvement in areas with frequent water vapor exchange.
作者
崔宏环
朱超杰
杨尚礼
胡淑旗
CUI Honghuan;ZHU Chaojie;YANG Shangli;HU Shuqi(Civil Engineering College,Hebei University of Architecture,Zhangjiakou 075000,Hebei,China;Hebei Provincial Key Laboratory of Civil Engineering Diagnosis,Reconstruction and Disaster Resistance,Hebei University of Architecture,Zhangjiakou 075000,Hebei,China)
出处
《华南理工大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2022年第2期42-49,共8页
Journal of South China University of Technology(Natural Science Edition)
基金
国家自然科学基金资助项目(51878242)
河北省教育厅重点项目(ZD2020325)。
关键词
水泥改良土
路用性能
干湿循环
加州承载比
无侧限抗压强度试验
cement-modified soil
road performance
drying-wetting cycle
California bearing ratio
unconfined compression test
