季冻区高铁路基改良粗颗粒填料冻融特性试验研究  

Experimental research on freezing and thawing characteristics of improved coarse grain filling material for high-railway foundation in seasonal freezing area

作　　者：崔宏环 王伟浩 邵博源 王小敬 闫利 朱超杰 CUI Hong-huan;WANG Wei-hao;SHAO Bo-yuan;WANG Xiao-jing;YAN Li;ZHU Chao-jie(Hebei Key Laboratory of Civil Engineering Diagnosis and Reconstruction and Disaster Resistance,Zhangjiakou 075000,Hebei,China;School of Civil Engineering,Hebei Institute of Civil Engineering,Zhangjiakou 075000,Hebei,China;North Prosperous Construction Group Co.,Ltd.,Chengde 067000,Hebei,China)

机构地区：[1]河北省土木工程诊断改造与抗灾重点试验室,河北省张家口075000 [2]河北建筑工程学院土木工程学院,河北省张家口075000 [3]北旺集团有限公司,河北承德067000

出　　处：《安全与环境学报》2022年第2期770-777,共8页Journal of Safety and Environment

基　　金：国家自然科学基金项目(51878242);河北省教育厅重点项目(ZD2020325);河北建筑工程学院创新基金项目(XY202012)。

摘　　要：针对季冻区高铁路基冻胀融沉问题及高铁安全运营的高要求,利用水泥和粉煤灰改良路基的填料,并通过自制冻融试验装置模拟填料的冻胀融沉条件,研究改良粗颗粒填料在冻胀融沉过程中的温度变化、冻胀率和融沉系数的规律,并评价改良填料的适用性。结果表明:在冻融温度变化过程中,水泥改良填料和水泥-粉煤灰改良填料均有减小填料导热和冻深的能力,且粉煤灰会小幅提升水泥填料的导热能力;改良填料在任一个冻融循环和冻胀阶段条件下的冻胀率均小于相同条件下的未改良填料;冻融循环对水泥-粉煤灰填料在慢降阶段的融沉作用影响较大;水泥填料在各阶段的融沉作用受第二次冻融循环影响较大;两种改良粗颗粒填料均有适用性,且添加5%水泥的改良填料最优。In view of the problem of frost heave and thawing settlement of high-speed railway subgrade in seasonal freezing areas and the high requirements for the safety operation of high-speed railways,this study used cement and fly ash to modify the filling material of subgrade,and the self-made freeze-thaw test device was used to simulate the frost heave and thaw sedimentation conditions of the filling material.The study content mainly included the temperature change,the frost heave rate and the thawing coefficient during the frost heave and thawing process,and the applicability of the modified coarse-grained filling material.The results show:modifiers can reduce the maximum dry density of coarse-grained filling material.In the process of freezing and thawing temperature changes,the steady-state temperature of the modified coarse-grained filling material is lower than the unmodified coarse-grained filling material at the same depth.Both the cement modified filling material and the cement fly ash modified filling material have the ability to reduce the thermal conductivity and freezing depth of the filling material,and fly ash can slightly increase the thermal conductivity of the cement filling material.In any freeze-thaw cycle and frost heave stage conditions,the frost heave rate of the modified filling material is lower than that of the unmodified filling material.In different stages,the frost heave rate of the modified coarse-grained filling material shows an increasing trend with the increase of the number of freeze-thaw cycles.The freeze-thaw cycle has a greater effect on the thawing sedimentation of the cement fly ash filling material in the slow-falling stage.The second freeze-thaw cycle affects the thawing sedimentation of the cement filling material in each stage.By the comprehensive consideration of the freezing and thawing characteristics of the filling material,the modified coarse-grained filling material is applicable,and cement filling material with 5%cement content is the best.

关 键 词：安全工程 高铁路基 改良粗颗粒填料 温度变化 冻胀率 融沉系数 

分 类 号：X951[环境科学与工程—安全科学]