Engineering Properties and Treatment of Hydraulically Reclaimed Saline Soil in Coastal Area

In order to meet the material demand of subgrade filling in the South Yellow Sea coastal area, where the soils are mainly from the hydraulic reclamation of land from the sea, a lot of laboratory experiments were conducted to evaluate the engineering properties such as salinity content, particle composition, limited water content, compaction characteristic, capillary water characteristic, resilient modulus, California Bearing Ratio (CBR), shear strength and so on. It turns out that the groundwater table is only 0.4~0.6m beneath the surface and this kind of hydraulic fill is chlorine saline soil with about 0.6%~0.7% salinity. The resilient modulus is about 38Mpa and CBR is only 2% at 96% degree of compaction with the optimum water content of 17.5%, which cannot satisfy the requirement of the current specifications of subgrade design because of the high groundwater. Lime and lime with cement are used to treat this chlorine saline soil respectively and the unconfined compressive strength shows that the 6% lime treated soil can be used in the roadbed of the subgrade while the 4% lime with 4% cement treated soil is comparatively good, resilient modulus and CBR of treated soil are significantly improved to 1180Mpa and 96% at 28 days age so that it can be used in the base layer. In conclusion, this kind of hydraulically reclaimed saline soil can be taken as the subgrade and base layer filling after treatment.