李慎刚, 石云方, 刘晋宁, 蒋琛. 碎石土路基填料压实及渗透特性[J]. 工程科学学报, 2024, 46(5): 918-926. DOI: 10.13374/j.issn2095-9389.2023.05.28.002
引用本文: 李慎刚, 石云方, 刘晋宁, 蒋琛. 碎石土路基填料压实及渗透特性[J]. 工程科学学报, 2024, 46(5): 918-926. DOI: 10.13374/j.issn2095-9389.2023.05.28.002
LI Shengang, SHI Yunfang, LIU Jinning, JIANG Chen. Research on compaction and permeability characteristics of gravel soil roadbed filler[J]. Chinese Journal of Engineering, 2024, 46(5): 918-926. DOI: 10.13374/j.issn2095-9389.2023.05.28.002
Citation: LI Shengang, SHI Yunfang, LIU Jinning, JIANG Chen. Research on compaction and permeability characteristics of gravel soil roadbed filler[J]. Chinese Journal of Engineering, 2024, 46(5): 918-926. DOI: 10.13374/j.issn2095-9389.2023.05.28.002

碎石土路基填料压实及渗透特性

Research on compaction and permeability characteristics of gravel soil roadbed filler

  • 摘要: 为揭示碎石土路基填料在压实及渗透过程中的颗粒破碎、流失规律,对不同含石量及含水率的碎石土试样进行击实及击实后的渗透试验. 结果表明:对于碎石为硬岩、细颗粒为砂类土的碎石土试样,在碎石质量分数(简称含石量)为60%时达到最大干密度;击实破碎前后的粒径分布具有良好的分形特征,分形维数D与干密度呈现正相关,破碎最优分形维数区间粗颗粒为2.23 ~ 2.25、细颗粒为2.43 ~ 2.45;建立了分形维数D与含石量和含水率的关系式可以对分形维数D进行预测并进一步估计压实效果;破碎率Bg与分形维数D也有良好的线性关系,含石量不超过60%时,粗、细颗粒的分形维数D均随颗粒破碎率Bg的增加而增加;渗透侵蚀对分形维数D的影响受含石量的影响较大,60%含石量时,分形维数差值随含水率的增大先减小后增大,与渗透系数的变化趋势相同. 含石量和含水率是影响颗粒破碎、流失的两个重要因素,但相对于含水率而言,含石量对颗粒破碎、流失的影响更加显著,分形维数D与各配比试样的击实、渗透试验结果的相关性良好,能够较好地反映碎石土试样的压实及渗透特性,可进一步揭示碎石土路基的压实机理,也可为路基工程施工提供参考.

     

    Abstract: To elucidate the rules of particle crushing and loss of gravel soil subgrade filler during compaction and penetration, we performed compaction and permeability tests of gravel soil samples with different stone and moisture contents; moreover, crushing condition and fractal analysis were also performed on the test results. The results reveal that the best compaction effect is achieved when the stone content is 60% for gravel soil samples with hard rocks and fine particles as sandy soil and optimal moisture content is 8%. With the exception of the 70% stone content, the permeability coefficients of each ratio are similar, and the permeability coefficients all range from 10−2 to 10−3, indicating good permeability. The particle size distributions before and after compaction and crushing exhibit good fractal characteristics. The fractal dimension D is positively correlated with the dry density. Furthermore, the optimal fractal dimension D for crushing is 2.23–2.25 and 2.43–2.45 for coarse and fine particles, respectively. Relationships between the fractal dimension D and stone and moisture contents are established. Based on the relationship and optimal fractal dimension interval, the fractal dimension D can be predicted, and the compaction effect can be further estimated. There is also a good linear relationship between the crushing ratio Bg and fractal dimension D. When the stone content is no more than 60%, D of the coarse and fine particles increases with increasing Bg. The relationship between the fractal dimension D and penetration erosion shows that the smaller the difference between the fractal dimension before and after penetration, the smaller the effect of penetration on the erosion of gravel soil. The permeation erosion effect on D is highly affected by the stone content. When the stone content is 60%, the difference in fractal dimension decreases first and then increases as the moisture content increases, which is consistent with the changing trend of the permeability coefficient. Moreover, stone and moisture contents are two important factors that affect particle crushing and loss. However, stone content has a more significant impact on particle crushing and loss than moisture content. The fractal dimension D has a good correlation with the compaction and permeability test results of each proportion sample, which can better reflect the compaction and permeability characteristics of gravel soil samples. Thus, the results of this study can further reveal the compaction mechanism of gravel soil subgrade and provide a reference for subgrade construction.

     

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