Studies on the Subsoil Improvement of Sea Bottom Polder based on the Analysis of Salt and Ion Behavior in Clayay Soil

采用室内试验和现场试验相结合的方法，对鹿儿冈滩涂石膏后的地基改良过程进行了研究。研究结果如下：1.现场研究表明，石膏提供的钙离子与吸附的钠离子发生交换反应，使扩散双电层减少，自由水增加。因此，石膏混合层中的分散反应得到了控制，土壤进入了浮选状态。同时，土壤物理性质的改善也有所收获。结果表明，土壤沉降量是钠粘土石膏改良进度最合适的判断标准。从1985年到1986年，对钙离子吸附钠的进展情况进行了追踪和研究。1984年底，将石膏分散混合至50 cm深度，并根据考虑空间变化的阳离子交换反应的合理方程计算出石膏的量。相应地，交换进展顺利，地基改良显著。此外，盐浓度的长期下降已经变得明显。

The Fieid studies and laboratory experiments about a process of subsoil improvement after gypsum dressing into Kasaoka polder had been carried out. The results are as follows;1. The field study showed the decrease of diffusion double layer and increase of free water because of the exchange reaction of adsorbed sodium ion by calcium ion supplied from gypsum. Consequently, the dispersion reaction in gypsum mixed layer had controled and soil changed to floculation state. At the same time, the improvement of soil physical characteristics had gained.2. It was showed that the sedimentation volumes of soils was most adequate judgment standard for the improvement progress of sodium clay with gypsum.3. The progressive situation of adsorbed sodium to calcium ion had been pursued and investigated from 1985 to 1986. The gypsum was scatterd and mixed until 50cm depth in the end of 1984 and its quantity was calculated from rational equation of cation exchange reaction considering spatial variance. Accordingly, the exchange had progressed smoothly and the subsoil improvement was remarkable. Furthermore, the long-term decline of salt concentration had become clear.