Study On Graded Gravel Subgrade Construction Technique Of Qin-Shen Express Railway

Qin-Shen(Qinghuangdao-Shenyang) special passenger railway is the first double-track electric railway with standard gauge and a designed speed above 200km per hour. It is the strategic decision for Chinese railway to fully participate in the market competition and to realize the high speed of passenger transport. In order to build this high-grade railway with the most technologic content, the strictest technical standard, and the fastest designed speed, we adopted a brand-new design and construction idea and thus largely promoted the building standard of the railway structure. Therefore, we have placed unprecedented emphasis' on the subgrade, holding the point of view that the quality of subgrade is the key to the success of the project construction. On the basis of improving the quality of subgrade filler and the roller compaction standard, we have specially consolidated the subgrade bedding and for the first time designed and adopted the new structure of the bedding surface of graded crushed stone. Because of that, we have no existing experiences for reference no matter in design or in construction. As a result, we have met with a series of technologic problems in the large-scale project construction. To this effect, this thesis carries out in-depth analysis for the construction technology of graded crushed stone in the bedding surface of Qin-Shen special passenger railway in combination with research of related scientific studies.This thesis collects the data of subgrade technical standards for railways in Japan, Germany, and France as well as the current railways at the speed of 140km, 160km, 200km, and 300km per hour in China, analyzes and compares the features of technical standards of railway subgrade both in China and abroad as well as the development of technical standards of railway subgrade of different speeds in China, grasps the similarities and differences in terms of engineering technologies such as subgrade structure, filler control, and compaction standard etc., and finally gives some viewpoints and suggestions on the shortcomings of the existing technical standards of railway subgrade in China.Combining with the spreading and compaction of graded crushed stones on the surface layer of subgrade bedding in Bid Section A12 and Bid A13 of Qin-Shen Special passenger railway, research on construction technologies such as material...