摘要
和若铁路(和田—若羌)DK111+500—DK111+800段的风积沙为C3间断级配细沙,不能直接用作铁路路基基床填料。为了对风积沙进行改良,考虑在其中单独掺加聚丙烯纤维,以及将聚丙烯纤维分别与玄武岩纤维、玻璃纤维、聚酯纤维按质量比1∶1复掺。不管单掺还是复掺,纤维掺量(质量分数)均分别取6‰、8‰、10‰,水泥掺量(质量分数)为5%,养护龄期7 d。通过无侧限抗压强度试验,研究不同纤维单掺和复掺对水泥改良风积沙应力、应变、无侧限抗压强度和割线模量的影响。结果表明:与相同掺量的单掺试样相比,掺量为6‰、8‰时复掺聚丙烯纤维与玻璃纤维试样峰值应力小幅增大,其他复掺试样峰值应力均减小;不同纤维复掺对水泥改良风积沙无侧限抗压强度增强效果不明显,但对水泥改良风积沙割线模量影响明显;掺量8‰时复掺聚丙烯纤维与玻璃纤维试样无侧限抗压强度比单掺试样增大6.53%,而其他复掺试样无侧限抗压强度均比相同掺量单掺试样减小0.21%~11.73%;不同掺量下复掺试样割线模量均比单掺试样大,掺量6‰时复掺聚丙烯纤维与玄武岩纤维试样割线模量比单掺试样增加了1.12倍。研究结果可为沙漠地区铁路路基基床表层填料改良设计及施工提供参考。
The aeolian sand in the section DK111+500—DK111+800 of the Heruo Railway(Hotan-Ruoqiang)is C3 intermittent graded fine sand and cannot be directly used as filling material for railway subgrade beds.In order to improve the aeolian sand,it is considered to mix polypropylene fiber alone,as well as to mix polypropylene fiber with basalt fiber,glass fiber,and polyester fiber separately,with a mass ratio of 1∶1.Regardless of whether it is a single or complex addition,the dosage(mass fraction)is taken as 6‰,8‰,and 10‰,respectively.The cement content(mass fraction)is 5%,and the curing period is 7 d.By conducting unconfined compressive strength tests,the effects of different fiber single admixture and composite admixtures on the stress,strain,unconfined compressive strength,and secant modulus of cement modified aeolian sand was studied.The results showed that compared with single admixture specimen with the same dosage,the peak stress of composite polypropylene fiber and glass fiber specimen increases slightly at dosage of 6‰and 8‰,while the peak stress of other composite specimen decreases.The enhancement effect of different fiber composites on the unconfined compressive strength of cement modified aeolian sand is not significant,but it has a significant impact on the secant modulus of cement modified aeolian sand.When the dosage is 8‰,the unconfined compressive strength of the composite polypropylene fiber and glass fiber specimens increases by 6.53%compared to the single admixture specimen,while the unconfined compressive strength of other composite specimens decreases by 0.21%~11.73%compared to the single admixture specimen with the same dosage.The secant modulus of composite specimens with different dosages is higher than that of single admixture specimen.When the dosage is 6‰,the secant modulus of composite polypropylene fiber and basalt fiber specimen increases by 1.12 times compared to single admixture specimen.The research results can provide reference for the improvement design and construction
作者
邓林飞
DENG Linfei(China Railway Siyuan Survey and Design Group Co.Ltd.,Wuhan 430063,China)
出处
《铁道建筑》
北大核心
2024年第6期136-139,共4页
Railway Engineering
关键词
铁路路基
复掺纤维
试验研究
水泥改良风积沙
基床表层填料
无侧限抗压强度
割线模量
railway subgrade
composite fiber
experimental research
cement improved aeolian sand
surface filling material of subgrade bed
unconfined compressive strength
secant modulus
