摘要
和若铁路经过新疆塔克拉玛干沙漠南缘,夏季大气温度最高为46℃,地表温度最高可达70℃。为了研究养护温度对水泥改良风积沙微观孔隙结构的影响,开展不同养护温度下水泥改良风积沙核磁共振试验。试样养护温度分别为30℃,40℃,50℃,60℃,70℃和80℃,水泥掺量分别为4%和5%。研究结果表明:T2弛豫时间分布范围为0.1~10000 ms。随着养护温度的升高,水泥改良风积沙的T2谱分布曲线向右偏移即向孔径增大的方向移动,孔隙率和最可几孔径增大,水泥改良风积沙内部小孔和大孔占比增大,中孔占比减少。当水泥掺量从4%增大到5%后,水泥改良风积沙T2谱分布曲线向孔径减小的方向移动,孔隙率和最可几孔径减小,水泥改良风积沙内部中孔和大孔占比减小,小孔占比增多。水泥改良风积沙的无侧限抗压强度随孔隙率增大而呈幂函数降低。研究成果可为水泥改良风积沙铁路路基基床的设计和施工提供参考。
The Heruo Railway passes through the southern edge of the Taklimakan Desert in Xinjiang,where the maximum atmospheric temperature in summer is 46℃and the surface temperature can be as high as 70℃.In order to study the effects of curing temperature on the microscopic pore structure of cemented aeolian sand,nuclear magnetic resonance tests of cemented aeolian sand under different curing temperatures were carried out.The curing temperature of the samples were 30℃,40℃,50℃,60℃,70℃and 80℃,and the cement content was 4%and 5%.The results show that the distribution range of T2 relaxation time is 0.1~10000 ms.With the increase of curing temperature,the T2 spectrum distribution curve of cemented aeolian sand shifts to the right,that is,to the direction of increasing pore size,the porosity and the mean pore-size increase.The proportion of small pores and large pores inside the cemented aeolian sand increases,while the proportion of medium pores decreases.When the cement content increases from 4%to 5%,the T2 spectrum distribution curve of cemented aeolian sand shifts to the direction of decreasing pore size,and the porosity and the mean pore-size decrease.The proportion of medium and large pores in the cemented aeolian sand decreases,and the proportion of small pores increases.The unconfined compressive strength of cemented aeolian sand decreases in a power function with the increase of porosity.The results can be used as a reference for the design and construction of cemented aeolian sand railway subgrade bed.
作者
马超
郑世龙
阮波
张向京
徐斌
MA Chao;ZHENG Shilong;RUAN Bo;ZHANG Xiangjing;XU Bin(China Railway Siyuan Survey and Design Group Co.,Ltd.,Wuhan 430063,China;School of Civil Engineering,Central South University,Changsha 410075,China)
出处
《铁道科学与工程学报》
EI
CAS
CSCD
北大核心
2022年第5期1270-1278,共9页
Journal of Railway Science and Engineering
基金
国家自然科学基金资助项目(51878666)。
关键词
水泥改良风积沙
养护温度
核磁共振
T2谱
孔隙率
最可几孔径
孔径分布
cemented aeolian sand
curing temperature
nuclear magnetic resonance
T2 spectrum
porosity
mean pore-size
pore-size distribution
