摘要
土体的宏观工程力学性质受土体微细结构状态和变化规律的影响,其复杂的物理力学特性是微细结构特性的本质体现。为探明宏观土体沉降现象背后的本质机理,对德州地区沉降中心附近土体进行钻孔取芯,对五组不同深度土体试样进行不同荷载下的固结试验与SEM电镜扫描试验,探讨不同深度粘性土随着固结压力变化,土体压缩性及其微观结构的变化规律,总结土体微结构特征与微观参数变化特征,以期从细观本质机理上解释德州地区地面沉降的宏观现象。结果表明,随着固结压力的变化,土体的平均颗粒面积呈增大趋势,土体颗粒扁圆度提高。单元体排列概率熵均呈明显下降趋势,土体颗粒与土内孔隙分布定向性提高。不同深度的五组土体孔隙分布分维数均呈下降趋势且最终趋于稳定,颗粒分布分维数则明显上升,土体密实程度提高。
The macroscopic engineering mechanical properties of soil are influenced by the state and variation of soil microstructure,and its complex physical and mechanical properties are the essential embodiment of microstructure characteristics.In order to find out the essential mechanism behind the macroscopic soil subsidence phenomenon,the core of soil is drilled near the settlement center of Dezhou area,and consolidation experiment and SEM observation were carried out for five groups of soil samples with different depth and subjected to different loads.The change of soil compressibility and its microstrueture with consolidation pressure in different depth are discussed,and the characteristics of microstructure and parameters of soil are summarized.The aim is to explain the macroscopic phenomenon of land subsidence in Dezhou area from the mesoscopic essential mechanism of.Results show that with the change of consolidation pressure,the average particle size of soil is increasing and the soil particles have a higher degree of flatness.The probability entropy of the soil particle arrangement was significantly decreased,and the distribution of soil particles was more targeted.The distribution fractal dimension of the five groups of soil in different depths falls down and remains stable ultimately,while the fractal dimension of particle distribution increases obviously, and the soil compaction degree increases.
作者
李康
贾超
狄胜同
杨亚宾
何玥
虞未江
LI Kang;JIA Chao;DI Sheng-tong;YANG Ya-bin;HE Yue;YU Wei-jiang(School of Civil Engineering,Shandong University,Jinan 250061,Shandong,China;No.2 Hydro-engineering Geology Brigade of Shandong Provincial Bureau of Geology,Dezhou 253072,Shandong,China)
出处
《实验力学》
CSCD
北大核心
2019年第1期38-46,共9页
Journal of Experimental Mechanics
关键词
细观力学
微观结构
颗粒特性
地面沉降
图像处理
mesoscopic mechanics
microscopic structure
particle characteristics
land subsidence
image processing
