摘要
河北省西北地区特殊气候环境下,经上部荷载作用基床底层收缩变形产生的裂隙向上扩展使得路基表层产生裂缝。针对这一问题,本文以该地区路基改良粗粒土填料为研究对象,分析其力学特性与收缩特性,并提出新的抗裂评价指标,综合评价填料工程适用性。结果表明:掺入粉煤灰后水泥改良填料力学性能降低,但填料拉压比增大;水泥掺量越低填料抗干缩性能越好,掺入粉煤灰填料抗干缩性能进一步改善,但粉煤灰存在最佳掺量;填料最大温缩应变随温度的循环逐渐增加,第3次温度循环后趋于平稳,填料对温度变化敏感度降低;从能量角度提出综合抗裂系数,得出水泥粉煤灰改良填料综合抗裂性优于水泥改良填料。
Under the special climatic environment in the northwest of Hebei Province,cracks in the surface layer of the subgrade are formed due to the upward expansion of cracks caused by the shrinkage deformation of the bottom layer of the subgrade under the action of upper loads.Aiming at this problem,this paper would take the improved coarse-grained soil filler for subgrade in this area as the research object,analyze its mechanical properties and shrinkage characteristics,and propose new crack resistance evaluation indicators to comprehensively evaluate the engineering applicability of the filler.The results showed that the mechanical properties of cement improved filler decreased after adding fly-ash,but the tensile compression ratio of filler increased.The lower the cement content,the better the dry shrinkage resistance of the filler,and the further improvement of the dry shrinkage resistance of the filler mixed with flyash,but there is an optimal content of fly-ash.The maximum temperature shrinkage strain of the filler gradually increases with the temperature cycle,tends to stabilize after the third temperature cycle,and the sensitivity of the filler to temperature changes decreases.From the perspective of energy,the comprehensive crack resistance coefficient is proposed,and it is concluded that the comprehensive crack resistance of cement fly-ash improved filler is better than that of cement improved filler.
作者
崔宏环
赵嘉
胡峻晖
谢直树
CUI Honghuan;ZHAO Jia;HU Junhui;XIE Zhishu(Hebei Key Laboratory of Civil Engineering Diagnosis,Reconstruction and Disaster Resistance,Zhangjiakou Hebei 075132,China;School of Civil Engineering,Hebei University of Civil Engineering and Architecture,Zhangjiakou Hebei 075132,China)
出处
《铁道建筑》
北大核心
2023年第3期137-142,共6页
Railway Engineering
基金
河北省高等学校科学技术研究项目(ZD2020325)。
关键词
高速铁路路基
抗裂性能
试验研究
粗粒土填料
力学特性
收缩特性
high speed railway subgrade
crack resistance
experimental research
coarse-grained soil filler
mechanical properties
shrinkage characteristics
