固化硫酸盐渍土水盐迁移的试验研究

Experimental study on water and salt migration of solidified sulphate saline soil

盐渍土地基中毛细水上升必然带动土体内盐分向上迁移聚集。采用土柱毛细水上升试验,模拟全开放自然条件下盐渍土的水盐迁移特征,测量不同时间梯度迁移后含水率、Cl^-和SO4^2-的变化,比较在蒸馏水和复合盐迁移液下的压实盐渍土和石灰粉煤灰水玻璃固化硫酸盐渍土毛细水盐迁移特征。试验结果表明:固化盐渍土中的毛细迁移速率和Cl^-、SO4^2-的迁移速率均小于压实盐渍土,说明固化盐渍土有减缓毛细水上升和阻碍盐分迁移的作用;毛细水迁移稳定后,压实土中含水率沿高度呈线性减少趋势,固化土中含水率沿高度先线性增大后保持不变,说明固化土具有稳定持水作用;在迁移过程中,含水率、Cl^-和SO4^2-迁移规律具有一致性,Cl^-迁移速率大于SO4^2-。试验说明固化硫酸盐渍土不仅具有强度上的提高,同时可以阻滞盐分,尤其是硫酸离子的向上运移。

The rising of the capillary water in the saline soil foundation will inevitably lead to the upward migration and aggregation of salinity in the soil. The characteristics of the water and salt migration in saline soil were simulated by the test of the capillary water rising under the natural conditions. The changes of water content,Cl- and SO42-at different times were measured after the gradient migration,and the characteristics of the capillary water and salt migration between the compacted saline soil and sulphate saline soil solidified by lime fly ash water glass were compared under the distilled water and compound salt solution. The results show that the rates of the capillary migration and Cl- and SO42-migration in the solidified saline saline soil are less than those in the compacted saline soil,which indicates that the solidified soil has the effect on slowing down the rising of the capillary water and hindering the salt migration. After the stabilization of capillary water migration,the water content of the compacted soil decreases linearly and the water content in the solidified soil decreases linearly first and then stay the same along the height,indicating that the solidified soil has a stable water-holding ability. During the migration process,the migration rules of the water content,Cl- and SO42-are consistent and the migration rate of Cl- is greater than that of SO42-. The experiments show that the solidified sulphate saline soil not only has an improvement of strength,but also can block the upward migration of salinity especially the upward migration of sulphate ion.