温度循环变化条件下高铁路基改良粗颗粒填料温缩特性研究
Study on Thermal Shrinkage Characteristics of Improved Coarse-Grained Soil Fillers for High-Speed Railway Embankments in Temperature Cycles
赵嘉 1崔宏环 1谢直树 2胡峻晖2
作者信息
- 1. 河北建筑工程学院,河北张家口 075000;河北省土木工程诊断、改造与抗灾重点试验室,河北张家口 075000
- 2. 河北省土木工程诊断、改造与抗灾重点试验室,河北张家口 075000
- 折叠
摘要
针对高铁在寒冷地区运行稳定的高要求,选取河北地区代表性的两个温差环境进行温度循环,研究填料种类、温度循环次数、温差区间对改良粗颗粒填料温缩应变特性的影响.结果表明:水泥改良填料具有较大的温缩应变和温缩系数,粉煤灰的掺入减小了水泥改良填料的最大温缩应变和平均温缩系数,但粉煤灰掺量不宜过大;随着温度循环的进行,填料的最大温缩应变先增大,经历第三次循环后逐渐平稳.对比不同温度循环环境下改良填料的温缩系数,得出经历多次温度循环后改良填料对温度变化的敏感程度降低;提出应变损失率和应变恢复率的概念,得出在水泥粉煤灰改良填料中少量增大水泥掺量有助于提高填料应变恢复率,但该作用在-20～30 ℃环境并不明显;推荐在河北地区的高铁路基建设中使用水泥掺量3％～5％、粉煤灰掺量12％～20％的改良粗颗粒填料.
Abstract
In view of the high requirement for smooth operation of high-speed railway in cold regions,two representative temperature difference environments in Hebei region were selected and the effects of filler types,temperature cycles and temperature difference intervals on thermal shrinkage strain characteristics of improved coarse-grained soil fillers were studied.The results indicated that the fillers improved with cement had larger thermal shrinkage strain and thermal shrinkage coefficients,and the mixing of fly ash reduced the maximum thermal shrinkage strain and average thermal shrinkage coefficients,but the mixing ratio of fly ash could not be too large,the maximum thermal shrinkage strain of the fillers increased first and leveled off after the third cycle.Comparisons of thermal shrinkage coefficients of improved fillers that had undergone temperature cycles in different temperature intervals,it was found that the sensitivity of improved fillers to temperature changes decreased after experiencing multiple temperature cycles.The ratios of strain loss and strain recovery were proposed.Furtherly,it was concluded that mixing a little amount of cement into the improved fillers could improve the strain recovery ratio,but the effect was not obvious in the environment of -20 ℃ to 30 ℃.It was suggested that in the construction of high-speed railway in Hebei province,the im-proved coarse-grained soil fillers with the cement mixing ratios of 3％to 5％and fly ash mixing ratios of 12％to 20％should be used.
关键词
高铁路基/改良粗颗粒填料/粉煤灰/温缩性能Key words
high speed railway embankment/improved coarse-grained filler/fly ash/temperature shrink-age characteristic引用本文复制引用
基金项目
国家自然科学基金(51878242)
张家口市重点研发计划(2221026B)
出版年
2024
NETL
NSTL
万方数据