Research On The Technology Of Saline Soil Subgrade Treatementin Tianjin Binhai New Area

In condition of great temperature difference, upper underwater table, much clay, more height of capillary rise, higher precipitation intensity, etc., saline soil in Binhai new area show features as follows: salt accumulation in the top in spring, salt crystallizing with the density of salt resolution, serious capillary action. Considering of the local material's current situation, inorganic binding materials was used to consolidate chlorine saline soils as Subgrade padding. This topic first test and analyze the chlorine saline soil's geotechnical properties in the Binhai area, and then on the basis of the obtained geotechnical properties, lime and fly ash was used to consolidate chlorine saline soil in Binhai area singly or mixed. After the compaction experiments on many kinds of consolidated soil, a systematic study on the mechanical properties and road-relate performance of consolidated chlorine saline soil was carried out, including the research on unconfined compression strength of different ages, California bearing ratio(CBR), limit salinity, anti-frozen performance and thermal shrinkage performance, water stabilizer performance, compressive resilience modulus, etc. In the research of the properties of frost resistance, a evaluation index of freeze-thaw stability times and anti-frozen stability coefficient have been proposed. Consolidation effect of different mix ratios have been comprehensive evaluated via the grey correlation theory and degree of deviation. On basis of the soil features of Binhai new area, proper mix ratios under different salinity saline soil which will be used for filling the embankment was proposed. The structure and morphology of the products from consolidation soil with different ages are characterized by X-ray powder diffraction (XRD) and field-emission scanning electron microscopy (FESEM). The morphology of the products infered the type of the products and test the results of XRD. The consolidation mechanism of inorganic binding materials to consolidate chlorine saline soil was systematicly studied. Binding material's strengthening technique and isolation layer technique was used to treat with salt dilate and collapsibility which are caused by saline soil in order to ensure the Subgrade durability and well road performance.