论文部分内容阅读
为探讨结构性土变形的微观机制,以湛江地区结构性黏土为研究对象,对原状土和压缩试验后土样进行压汞试验,分析不同固结压力下土的孔隙分布、孔径大小以及孔隙结构特征参数的变化规律,辅以SEM图像进行孔隙形态的定性分析,并从分形理论角度对此解释与验证。结果表明,湛江黏土各孔隙组对外力的敏感度与孔隙体积含量正相关。由于压汞过程存在瓶颈效应以及边-面-角的空间接触形式,其结果可能会夸大真实小孔隙的分布密度而低估大孔隙的分布密度。结构性对压缩过程中孔隙分布影响较大,当固结压力增大至结构屈服压力后,孔径为0.01~0.50μm的孔隙组变化明显,孔隙的连通性变差,孔径分布向小孔径范围移动,孤立式孔隙增多,大、中孔隙的界限变得不明显。湛江黏土孔隙具有多重分形特征,据此确定微裂隙、粒间孔隙和孤立孔隙孔径的分界点为0.01μm与0.50μm,同时给出了湛江黏土的孔径界定标准。
In order to discuss the microscopic mechanism of structural soil deformation, taking the structural clay in Zhanjiang as the research object, the mercury in the undisturbed soil and the soil after the compression test were tested by mercury injection. The pore distribution, pore size and pore structure under different consolidation pressures The variation of the characteristic parameters, combined with the SEM image qualitative analysis of pore morphology, and from the perspective of fractal theory to explain and verify. The results show that the sensitivity of Zongjiang clay to each external force is positively correlated with the pore volume. Due to the bottleneck effect of mercury injection and the space-contact form of edge-surface-angle, the results may exaggerate the distribution density of true small pores and underestimate the distribution density of large pores. When the consolidation pressure increases to the structural yield pressure, the pore group with pore size of 0.01 ~ 0.50μm changes obviously, the connectivity of pores decreases, and the pore size distribution moves to the small pore size range , Isolated pores increased, the boundaries between large and medium pores became insignificant. Zhanjiang clay has multifractal characteristics. Based on this, the demarcation points of micro-fissures, intergranular pores and isolated pore sizes are 0.01μm and 0.50μm, and the definition of the pore size of Zhanjiang clay is given.