Studies On The Impact Of Salt Content On Saline-alkali Soil Engineering Properties In The Songnen Plain

Saline soil is widely distributed in the earth, about quarter of land total area. It is distribute every continent in the world. Saline soil is widespread in our country too. There is a large quantity of saline-alkali soil in the Songnen Plain. The section of national highway 203 that from Songyuan to Jinbaotun is located southwest of Jinlin province. The soil basify serious. Some sections of highway where distributed saline-alkali soil exist road disease such as road surface subside and roadbed dent. Specifications for design of highway subgrades stipulate such soil cannot use for arterial highway subgrade stuffing because of the instability of the engineering properties. The cost of road construction will increase. The paper study engineering properties start with the basic property of saline-alkali soil with the sample in the area from Songyuan to Jinbaotun. The key is impact of salt content on property and mechanism analyze. The purpose is to offer suggest for improving saline-alkali soil that can use for highway and without road disease.We discovered some sections of highway distributed saline-alkali soil along the line from Songyuan to Jinbaotun with field investigation especially K198 and K145 segment. The old road destroyed to a certain degree. Soil is variety in 1 m depth. We also found that the soil have corrosive characteristics when sampling and testing.The salt component is mostly NaHCO3 in the soil. its salt content was ranged from 0.13% to 0.54%. We got soil grain gradation composition, mineral component, basic physics character datum, plasticity, permeability and so on through experimentation. We obtained undisturbed soil's shear strength from quick shear test.The plastic limit and liquid limit have bigger trend with salt content increasing. We obtained that the soil inceptive expansion increment largen and contractility is markedly increased as salt content increasing with swell-shrink characteristics test. The shear strength also changed with salt content. To a certain moisture content, the shear strength first reduce then increase with salt content increasing. In a word, the soil engineering properties worse or more instability with more salt content. It will affect on engineering construction and upkeep.