Study On The Ameliorated Saline Soil Of Expressway Subgrade

The paper selects typical saline soil of subgrade padding that is along the line of Jianyuguan to Anxi expressway to conduct the study of amelioration test and except to ameliorate and use saline soil as subgrade padding.Through the basic behavior tests study of saline soil, the paper determines the saline soil type and engineering characteristic. On the basis of that, the paper initially selects several kinds of ameliorants. Through short-period water stability tests of ameliorated saline soil, the paper finally determines the amelioration plan and proportion. According to the plan and proportion, the paper uses the tests of heavy compact to determine the optimum water content and the maximum dry density and provide the basis for mechanics tests and durability.The paper systematically studies the mechanics performance and durability of three plans of ameliorated saline soil. The mechanics performance and durability of three ashes ameliorating saline soil are best, the mechanics performance and durability of two ashes ameliorating saline soil are better, and the mechanics performance and durability of the lime ameliorating saline soil are poor. In the study of microcosmic-test, the paper determines the main resultant type of ameliorated saline soil through X-ray diffraction test; obtains existent direct proportion relations between the CaCO₃ content and heat loss in the resultants through differential thermal-thermogravimetric test; discovers the intensity increases with the microscopic appearance in columnar, acicular, laminated structure increasing through scanning electron microscopy. Combining the microcosmic-test, the paper analyzes the amelioration mechanism. Through the economic analysis of ameliorated saline soil, the paper appraises the influence of project cost. In view of construction of ameliorated saline soil, the paper provides the specific requests.