土石混合物击实特性的颗粒尺寸效应研究  

Study on Particle Size Effect of the Compaction Characteristic of Soil-Rock Mixture

作　　者：康凤 袁帅 Kang Feng;Yuan Shuai(CCCC Shec Dong Meng Engineering Co.,Ltd.,Xi'an 710061,China;College of Highway Engineering,Chang'an University,Xi'an 710064,China;Wuhu Surveying and Mapping Design Institute Co.,Ltd.,Wuhu 241000,China)

机构地区：[1]中交二公局东萌工程有限公司,陕西西安710061 [2]长安大学公路学院,陕西西安710064 [3]芜湖市勘察测绘设计研究院有限责任公司,安徽芜湖241000

出　　处：《市政技术》2024年第11期1-6,共6页Journal of Municipal Technology

基　　金：中国博士后基金面上项目(2022M722436)。

摘　　要：土石混合物击实特性存在颗粒尺寸效应,因此针对黄土、块石混合物开展了固定含石率、不同最大粒径和含水率条件下室内击实试验,获得了不同粒径土石混合物试样最佳含水率和最大干密度,并分析了颗粒尺寸效应对土石混合物击实效果的影响。研究结果表明,随着含水率的增大,试样从最开始脱模时产生塌落逐渐转变为完整状态,干密度逐渐增大。含水率超过最佳含水率后,水分子起到了润滑作用,将周边土体挤出,使整体体积不再减小,并呈软塑流动状,试样从完整脱模状态转变为脱模时产生较大变形。随着石料的加入,混合物最大干密度得到了明显提升,如在含石率为70%的条件下,最大粒径20、30、40 mm试样最大干密度的增长率分别为24.9%、28.1%、29.7%,且最大粒径越大,干密度提升效果越明显;最佳含水率随着最大粒径的增加而降低,在最大粒径20~40 mm的情况下,对应的最佳含水率为5.2%~5.9%,且随着最大粒径的增大,最佳含水率的变化量分别为0.2%、0.5%。因此可以看出,在70%含石率下,最大粒径20~40 mm范围内,随着最大粒径的增大,土石混合物最佳含水率的降低速率呈增大趋势。Particle size effect exists in the compaction characteristics of soil-rock mixture.In this paper,laboratory compaction tests are carried out under the conditions of fixed stone content,different maximum particle size and water content of loess and stone mixture,to obtain the optimal water content and maximum dry density of soil-rock mixture samples with different particle sizes.The impact of particle size on the compaction effect of soil-rock mixture are analyzed.The results show that the soil sample gradually changes from collapse to complete state and the dry density increases gradually with the increase of water content.When the water content exceeds the optimal water content,the water molecules play a lubricating role.The surrounding soil is extruded so that the overall volume is no longer decreases,showing a soft plastic flow state,and the sample has a large deformation from complete demoulding to demoulding.Wit h the addition of stone,the maximum dry density of the mixture is significantly increased.Under the condition that the stone content is 70%,the maximum dry density of the sample with the largest particle size of 20 mm,30 mm and 40 mm increase by 24.9%,28.1% and 29.7%,respectively.The larger the maximum particle size,the more obvious the dry density improvement effect.The optimal water content decreases with the increase of the maximum particle size.When the maximum particle size is 20~40 mm,the corresponding optimal water content is 5.2%~5.9%.With the increase of the maximum particle size,the optimal water content changes by0.2% and 0.5%,respectively.It shows that with the increase of the maximum grain size,the decrease rate of the optimal water content increases in the range of 20~40 mm under the condition of 70% stone content.

关 键 词：土石混合物 颗粒尺寸效应 击实试验 最大干密度 最佳含水率 

分 类 号：U414.1[交通运输工程—道路与铁道工程] TU411[建筑科学—岩土工程]