水泥改良千枚岩弃渣用作铁路路基填料的试验研究  

Experimental Study on Railway Subgrade Filling Material of Phyllite Spoil Improved with Cement

作　　者：张延杰[1,2] 王旭[1] 尹亚雄[3] 赵磊[1,2] 

机构地区：[1]兰州交通大学土木工程学院,甘肃兰州730070 [2]甘肃省道路桥梁与地下工程重点试验室,甘肃兰州730070 [3]中铁第一勘察设计院集团有限公司,陕西西安710043

出　　处：《铁道学报》2014年第6期81-86,共6页Journal of the China Railway Society

基　　金：长江学者和创新团队发展计划(IRT1139);兰州交通大学"青蓝"人才工程基金(QL-08-19A)

摘　　要：由于千枚岩弃渣耐崩解性差,不宜直接作为铁路路基填料。采用水泥对千枚岩弃渣进行改良,选取水泥掺合率、压实度和龄期3个主要影响因素,进行3因素4水平的正交试验设计,确定16组方案,同一方案进行3组平行试验。试验结果表明:用水泥对千枚岩弃渣进行改良后,无侧限抗压强度提高5倍以上,最大为3.5MPa;同时改良土的耐崩解性得到大幅度提高,具有较好的水稳定性,水泥的掺入对改良土的膨胀特性并无明显影响。采集改良千枚岩弃渣的扫描电子显微镜照片,并借助Leica QWin图像处理软件进行影像处理与计算。分析表明:水泥的掺入改变了土体的结构,明显增加颗粒间的连结程度。推荐使用5%的掺合率,能够满足Ⅰ、Ⅱ级铁路路基基床以下部位填料的设计要求。研究成果可供同类工程参考。Phyllite spoil is not applicable to be directly used as the filling material of railway subgrade because of its poor slake durability .The cement mixing rate ,degree of compaction and cement age were selected as the three influence factors to conduct 3 factor and 4 level orthogonal tests to improve phyllite with cement .16 schemes were fixed and each scheme included 3 parallel tests .The test results indicate as follows ：After cement is admixed as the modifying agent ,the unconfined compressive strength of phyllite spoil is increased by more than 5 times till the maximum value of 3.5 MPa;the improved phyllite spoil demonstrates greatly improved slake durability and good water stability ;the admixture of cement does not obviously affect the swelling charac-teristic of the improved phyllite spoil .Scanning electron microscope photos of the improved phyllite spoil were collected and processed and calculated by Leica QWin .The analysis shows as follows ：admixing of cement chan-ges the structure of the phyllite mass and greatly increases the degree of connection of phyllite particles ;the mixing rate of 5% is recommended ,w hich can meet the requirements of design of embankment filling under subgrade bed of railways gradesⅠ ＆amp; Ⅱ .The research results can provide valuable references to similar projects .

关 键 词：千枚岩 水泥改良 扫描电子显微镜 微结构 

分 类 号：U213.1[交通运输工程—道路与铁道工程]