泥沙研究

细颗粒泥沙絮凝影响其输移与岸滩演变，研究细颗粒泥沙的絮凝特性与机理具有重要意义。选取极细石英质粉砂作为典型非黏土矿物，以高岭土作为典型黏土矿物对照组，通过分析两种样本的级配、微观形态及其在不同浓度的NaCl与CaCl₂溶液中Zeta电位变化，研究石英质粉砂颗粒的絮凝特性。研究发现，极细石英质粉砂在清水中可发生絮凝，并以细颗粒聚合为主要絮凝形式。随着电解质溶液浓度升高，两种矿物颗粒表面Zeta电位均先陡增、后波动，但二者波动中心与幅度存在差异。粒径小于8μm的非黏土矿物组分絮凝后，其絮团电位随电解质浓度的变化趋势及级配参数与黏土矿物类似，建议对此类非黏土矿物泥沙颗粒采用黏性沙理论计算絮团尺寸与沉速。

The flocculation of fine-grained sediment significantly influences their transport behavior and coastal evolution, making it essential to understand their flocculation characteristics and underlying mechanisms. In this study, ultrafine quartz silt was selected as a representative non-clay mineral, with kaolinite serving as a typical clay mineral for comparison. The flocculation behavior of quartz silt particles was investigated by analyzing the grain size distribution, microscopic morphology, and Zeta potential variations of both samples in NaCl and CaCl₂ solutions with varying concentrations. Results indicate that ultrafine quartz silt can flocculate in freshwater, primarily through the aggregation of fine particles. As electrolyte concentration increases, the Zeta potentials of both minerals exhibit an initial sharp increase followed by fluctuations around a stable value. However, the fluctuation centers and amplitudes differ between the two samples. The trend of floc Zeta potential and gradation parameters of non-clay mineral components of particle size less than 8 μm with variation of electrolyte concentration are similar to those of clay minerals. It is suggested that cohesive sediment theory can be applied to estimate floc size and settling velocity for non-clay particles smaller than 8 μm.