PS对非饱和重塑黏土的土-水特征曲线的影响

Effect of PS on soil-water characteristic curve of remolded unsaturated clay

采用扫描电镜测试PS加固前后黏土微观结构的变化,研究黏土矿物、孔隙结构和土体收缩特性3种因素对加固以后非饱和重塑黏土的土-水特征曲线的影响。研究结果表明:PS与土颗粒的反应是非常复杂的物理化学反应,在反应中大量的黏土矿物被消耗,形成一种较致密的结构,力学强度提高,同时,孔隙壁变得光滑、平直,土颗粒磨圆度增大,膨胀性降低,这些因素导致非饱和黏土的土-水特征曲线发生明显变化;PS加固后饱和含水率和残余含水率都有一定程度下降,进气值较高,斜率变陡,下降速度快。Van Genuchten模型(即VG模型)对PS作用前、后的土-水特征曲线的拟合效果较好。研究结果证明PS材料加固土遗址的良好性能。

SEM was employed to analyze the micropore structure of remolded samples which were reinforced by PS or not. The effects of clay mineral, pore structure and shrinkage on the soil-water characteristic curve （SWCC） of remolded unsaturated clay after consolidating by PS were analyzed. The results show that PS can improve the mechanical property through binding separate earthen relics particle together, and a series of physical and chemical reactions between PS and particle surface also improve the clay behaviors of the remolded unsaturated clay, such as pore structure, psephicity and shrinkage, which lead to the change of SWCC of the unsaturated clay. The results also suggest that the characters of the samples including saturated water content, residual water content, air entry value and the slope of the SWCC are changed after consolidating by PS, the saturated water content and residual water content are lower while the air entry value and the slope of the SWCC become higher than that without PS. Van Genuchten model （i.e., VG model） fits the experimental data well. The conclusion proves the ~ood performance of PS consolidation for earthen sites well.