The Research On Construction Techonology And Quality Control For Filled Subgrade With Improved Expansive Soil

As the foundation of the track structure, the subgrade must have the characteristics of sufficient strength, high rigidity, good stability and excellent durability. To enhance the execution process and quality control will be the essential point for implementing the above-mentioned goals during the construction work.Heifei-Nanjing Railway Project is planned as the passenger-freight transport line with designed speed of 200Km/h, the subgrade accounts for 84.5% of the total line length. The filling materials along the line widely get the medium and weak expansiveness, they could only be used after being improved. This text would expatiate on improving technology, improvement property, subgrade filling workmanship concerning the expansive soil; means of quality control and examination; observation and analysis for the settlement and deformation in filling; and other aspects on the basis of the test and research data, the obtained achievements regarding the improvement of the expansive soil from the Feidong Trial Section of Hefei-Nanjing Railway Project by the Third Engineering Group Co., Ltd. of China Railways.In the exordium, the summarized depiction is first given about the concept of the expansive soil, structural property, distribution scope, endangering extent to the project, the understandable extent to the expansive soil both in China and abroad and the researching status. The basis of the subject selection, significance, and researching content are put forward in this text. The Chapter Two dissertates about property and expansiveness analysis of the expansive soil in two borrow areas of the Trial Section; improvement workmanship of four road-mix methods and plant-mix workmanship and flow process of the expansive soil; research on different improvement parameters; evaluation on economic targets and environmental influence; and research on workmanship parameters of filled subgrade with improved soil. The quality by the plant-mix method is found the best, it is therefore suggested to have it used broadly on the full section of the subgrade of the high speed railway line and the passenger-dedicated railway line over 200Km/h speed. Comparing the four road-mix methods it is found that the...