循环荷载作用下花岗岩残积土累积变形与湿化特性试验研究
来源期刊：中南大学学报(自然科学版)2013年第4期
论文作者：周德泉 谭焕杰 徐一鸣 周毅 孙义
文章页码：1657 - 1665
关键词：花岗岩残积土；压缩实验；平板载荷试验；累积变形；湿化
Key words：granite residual soil; compression test; plate loading test; accumulative deformation; humidification
摘 要：基于花岗岩残积土的矿物成分特殊、压实机理复杂、水理作用显著的实际情况，对土样采用X线衍射试验分析土样中的矿物成分；采用土工试验分析土样物理力学性质；采用压缩实验和平板载荷试验对比，研究循环荷载作用下累积变形与湿化规律，以便现场压实控制。研究结果表明：样品的白云母-伊利石质量分数为35%，高岭石约占27%；土样属于细粒土质砾，级配不良；填土的压缩曲线呈上凸型，回弹曲线呈下凹型；第i+1次压 缩-回弹曲线均位于第i次曲线下方，线形相似；随着等载压实遍数增加，沉降增量递减，累积沉降增大；超载压缩曲线回归到首次压缩曲线的延长线上，具有记忆效应；荷载越大，某次压缩总变形和永久变形也越大；循环荷载作用后的压实填土遇水产生湿化沉降；湿化土的压缩和回弹曲线均呈下凹型，超载越高，在相同压力作用下的变形越小；现场压实过程中，增加压路机能量比增加压实次数可取得较好的压实效果。
Abstract: Based on the fact that the granite residual soil has special mineral composition, complicate compacting mechanism and impressionable mechanism with water obviously, in order to guide practical compaction control, the mineral composition was analyzed by X-ray diffraction test, the physical and mechanical properties were analyzed by soil test, the accumulative and wetting deformation under cyclic loads were researched by compression test and plate loading test. The results show that the samples which have 35% (mass fraction) muscovite-illite, and 27% kaolinite，belong to fine grained soil gravel with bad gradation. The compression curves are convex type, while the rebound curves are concave type; the (i+1)th compression-rebound curves are below the ith with similar linetype. With the increase of the number of compaction operations under the same load, the increment of settlement decreases and accumulative settlement is enhanced. Overload compression curve can be regressed on the extension line of first compression curve, which has memory effect. When the load is larger, the total and permanent deformation becomes bigger each time. Wetting deformation occurs after humidification when circulate loading and unloading are finished. The compression curves of humidified soil are concave type, while the larger the overload is, the less the deformation under the same load.It’s better to increase the tonnage of the road roller than the increase of the number of compaction operations in the practical process of construction.
周德泉1，谭焕杰1，徐一鸣2，周毅2，孙义1
(1. 长沙理工大学 岩土与隧道工程系，湖南 长沙，410004；2. 广东省长大公路工程有限公司，广东 广州，510620)
摘 要：基于花岗岩残积土的矿物成分特殊、压实机理复杂、水理作用显著的实际情况，对土样采用X线衍射试验分析土样中的矿物成分；采用土工试验分析土样物理力学性质；采用压缩实验和平板载荷试验对比，研究循环荷载作用下累积变形与湿化规律，以便现场压实控制。研究结果表明：样品的白云母-伊利石质量分数为35%，高岭石约占27%；土样属于细粒土质砾，级配不良；填土的压缩曲线呈上凸型，回弹曲线呈下凹型；第i+1次压 缩-回弹曲线均位于第i次曲线下方，线形相似；随着等载压实遍数增加，沉降增量递减，累积沉降增大；超载压缩曲线回归到首次压缩曲线的延长线上，具有记忆效应；荷载越大，某次压缩总变形和永久变形也越大；循环荷载作用后的压实填土遇水产生湿化沉降；湿化土的压缩和回弹曲线均呈下凹型，超载越高，在相同压力作用下的变形越小；现场压实过程中，增加压路机能量比增加压实次数可取得较好的压实效果。
关键词：花岗岩残积土；压缩实验；平板载荷试验；累积变形；湿化
ZHOU Dequan1, TAN Huanjie1, XU Yiming2, ZHOU Yi2, SUN Yi1
(1. Department of Geotechnical and Tunnel Engineering, Changsha University of Science and Technology, Changsha 410004, China;2. Guangdong Provincial Changda Highway Engineering Co. Ltd., Guangzhou 510620, China)
Abstract:Based on the fact that the granite residual soil has special mineral composition, complicate compacting mechanism and impressionable mechanism with water obviously, in order to guide practical compaction control, the mineral composition was analyzed by X-ray diffraction test, the physical and mechanical properties were analyzed by soil test, the accumulative and wetting deformation under cyclic loads were researched by compression test and plate loading test. The results show that the samples which have 35% (mass fraction) muscovite-illite, and 27% kaolinite，belong to fine grained soil gravel with bad gradation. The compression curves are convex type, while the rebound curves are concave type; the (i+1)th compression-rebound curves are below the ith with similar linetype. With the increase of the number of compaction operations under the same load, the increment of settlement decreases and accumulative settlement is enhanced. Overload compression curve can be regressed on the extension line of first compression curve, which has memory effect. When the load is larger, the total and permanent deformation becomes bigger each time. Wetting deformation occurs after humidification when circulate loading and unloading are finished. The compression curves of humidified soil are concave type, while the larger the overload is, the less the deformation under the same load.It’s better to increase the tonnage of the road roller than the increase of the number of compaction operations in the practical process of construction.
Key words:granite residual soil; compression test; plate loading test; accumulative deformation; humidification
