STUDY ON SALINIZATION DEGREE AND ITS INFLUENTIAL FACTORS OF SALINE SOIL IN COASTAL AREA OF JIANGSU PROVINCE

Saline soil is one of the geological environment problems encountered in the construction of project in the coastal area. This paper takes saline soil samples shallower than 5 m depth to test the content of dissolvable salt,and studies the distribution principle,salinization degree and its influential factors of saline soil. The experiment results show that the distribution of saline soil is parallel to the coastline. Medium and weak saline soils take the majority and strong saline soil distributes sporadically. Salinization degree varies greatly under the influences of sedimentary environment,climate,hydrogeological conditions and human activities. In the horizontal direction,salt content and salinization degree are more and more obvious toward the coastal line,and strongly in the north but weakly in the south. Strong saline soil is distributed in the clayed soil area of Lianyungang. Lithology and groundwater mineralization serve as dominant influential factors. In the vertical direction,salt accumulation is common in the surface layer. The zoning in Lianyungang area is not obvious. Dafeng and Nantong districts can be divided into 3 zones from the shallow ground to the deeper layer,with salt accumulation section,changeable salt content section,and salt solution section. Groundwater level and soil layer construction serve as dominant influential factors. With the rapid promotion of grand development of the coastal area,to avoid the secondary salinization,it shall pay attention to the ground elevation loss derived from land subsidence,which would induce seawater intrusion and thus enhance the salinization of topsoil. In the engineering development,it can set isolated layer to cut off the capillarity of underground water with high salinity.