摘要
红层泥岩工程性质不良,常因降水-暴晒作用导致局部泥岩崩解软化而出现路基沉陷、路面开裂等问题。考虑环境因素影响作用,探究了干湿循环作用下红层泥岩的裂纹扩展规律及崩解特征,并对样品吸水量和核磁共振T2谱进行了测量,讨论了干湿循环作用下红层泥岩的崩解开裂机制。结果表明:在样品浸泡吸水阶段,裂隙主要产生于沿层理方向产生,裂缝的长度和宽度在5~6 h后随吸水时间增加而增大;垂直样品层理方向的裂隙集中产生于脱水初期0.5 h,当毛细孔水散失后,矿物失水收缩并随着脱水的持续裂隙逐渐闭合;第6次干湿循环后,崩解物颗粒从以粒径>10 mm的大颗粒为主逐渐过渡到以粒径<10 mm的小颗粒为主,并且崩解物越来越接近方形而非细长的颗粒;泥质粉砂岩内部水分存在重分布现象,泥岩样品内部所含的水主要为矿物结合水,为泥岩内大量膨胀矿物吸水提供了水的来源;泥质岩干湿循环作用下的崩解劣化过程为:泥岩原生缺陷存在→水分渗入原生缺陷→表面裂缝产生→水岩作用面积增强→裂缝扩展贯通→干湿循环作用→泥岩继续崩解至块状、颗粒状→最终崩解结束。研究可为将泥质粉砂岩作为路基填料的工程应用提供参考,工程应用价值显著。
The engineering properties of red-bed mudstone are poor,it often causes local mudstone to collapse and soften due to the precipitation-exposure effect,resulting in the problems such as subgrade settlement,pavement cracking.Considering the influence of environmental factors,the crack propagation rule and disintegration characteristics of red-bed mudstone under the action of dry-wet cycles are explored.The water absorption and nuclear magnetic resonance T,spectrum of the sample are measured,and the mechanisms of disintegration and cracking of red-bed mudstone under dry-wet cycles is discussed.The result shows that(1)In the water absorption stage of the sample,the cracks are mainly generated along the bedding direction,and the length and width of the cracks increase with the increase of water absorption time after 5-6 h.The fractures in the direction perpendicular to the bedding of the sample are occurred and concentrated at the initial stage of dehydration for O.5 h.After the capillary water is lost,the mineral shrinks due to water loss and gradually closes as the dehydration continues.(2)After the 6th dry-wet cycle,the disintegrated particles gradually transitioned from being dominated by large particles with diameter of>10 mm to being dominated by small particles with particle diameter of<10 mm,and the disintegrated particles became increasingly close to square rather than elongated particles.(3)There is a redistribution of water in pelitic siltstone.The water contained in the mudstone sample is mainly mineral bound water,which provides the source of water for a large number of swelling minerals in the mudstone to absorb water.(4)The disintegration and deterioration process of mudstone under the action of dry-wet cycles is:existence of primary defects in mudstone→primary defects of water infiltration→generation of surface cracks-→enhancement of water-rock interaction area→crack expansion and penetration→dry-wet cycle action→mudstone continues to disintegrate to massive and granular shape→end of disintegration finally.The research can provide a reference for the engineering application of pelitic siltstone as roadbed filler,with significant engineering application value.
作者
尹红亮
文良东
吴国庆
靖振帅
YIN Hong-liang;WEN Liang-dong;WU Guo-qing;JING Zhen-shuai(CCCC Infrastructure Maintenance Group Co.,Ltd.,Beijing 100011,China)
出处
《公路交通科技》
CAS
CSCD
北大核心
2023年第4期94-102,共9页
Journal of Highway and Transportation Research and Development
基金
住房和城乡建设部2020年度科技开发课题项目(2020-K-067)。
关键词
道路工程
红层泥岩
静态崩解试验
干湿崩解
形状特征
核磁共振
崩解机制
road engineering
red-bed mudstone
static disintegration experiment
dry-wet disintegration
shape feature
nuclear magnetic resonance
collapse mechanism
作者简介
通讯作者:尹红亮(1974-),男,河南洛阳人,硕士研究生,高级工程师.(32981124@qq.com)。
