Special Rock And Soil Roadbed Construction Technology And The Settlement Of Bridge Control Applied Research

With the development of road traffic in our country, there would be many highways which are builded on Mountain Areas and Hilly Area, while The special rock-soil mass distributed along the road is used as embankment filling material of express way. So, it is very important for theory and application to study project characteristics of the special rock-soil mass, and obtain its behavior in subgrade engineering. Yalu express way,because of complicated geological condition,has been classified as a model road of science and technology by the Ministry of Communications, and also has been classified as high grade project by Department of Communication of Sichuan Province. This paper is relyed on West Transportation Construction Science and Technology Project-"Study on Technology of Asbestos Tailing Used as Pavement Construction Materials" and Department of Communication of Sichuan Province project-"Study on Subgrade Building Technology of Express Way in Fluvioglacial Deposited Area", takes asbestos tailing and fluvioglacial deposits widely distributing along express way for example, embankment construction technology and quality control method of special rock-soil mass, and the control technology of differential settlement at the transition section between bridge abutment and embankment, is analyzed and researched. The main contents and results followings:(1)Based on existing investigation data and field survey, the causes, distribution rules and gradation feature of fluvioglacial deposited and asbestos tailings along way is confirmed, through sampling of exploration, in-situ test and so on, physical and mechanical parameters of fluvioglacial deposits are summed up, and then the basic engineering geological characteristics of fluvioglacial deposits is obtained, while though laboratory experiments, minerals and chemical constituents of asbestos tailings is primarily studied.(2)The applicability and road properties of asbestos tailings were confirmed, by a series of laboratory experiments. By in-situ tests section, comparison analyses are conducted to discuss compaction effect on different construction parameters, finally, the optimal construction plan that asbestos tailing used as embankment filling material of express way is obtained.(3)According to the characteristic of coarse grained soil roadbed, Sand cone replacement method and water-filling method is employed to detect compactness, meanwhile, using settlement differential method to detect compaction quality of subgrade. Based on the results of test section, compaction quality standard of every detection mode was confirmed, and the relationship of them is proposed, finally, the determination method of subgrade compaction effect was adopted, which use two control standards of compactness and settlement difference.(4)Based on summarizing the causes and hazard of bumping at bridge-head on express way, through investigating mileage and treatment measures of the transition section between bridge abutment and embankment at Yalu express way, and choose representative sections, the settlement was predicted by theoretical calculation, the influence of different construction parameters on post-construction settlement was discussed, on the basis of the calculation results, construction guiding plan and quality control standard of the transition section between bridge abutment and embankment were suggested.