Research On Settlement Characteristics And Treatment Technology Of Red Clay Foundation In High Speed Railway

In our country, with the rapid development of the national economy, in order to ease the tense situation of increasing railway transportation, the development of high-speed railway is imperative. The running speed of more than 200Km/h high speed railway train, is comfortable and smooth and safe performance, which requires the track with ride. High-speed railway Design Specification(TB 10621-2009) of China about ballastless track subgrade settlement has a strict rules, industry and trade control after the settlement is one of the important technical issues. The high speed railway in foreign countries realized the effective control of the post construction settlement through a certain method, but it is difficult to use these methods in our country to solve the problem of traffic bottleneck.In the construction of high-speed railway in our country, most of the foundation soil encountered in subgrade engineering belong to the category of medium compression soil. According to the design specification settlement calculation theory directly to it as the foundation of passenger dedicated line usually can not meet the design requirements, so in our country a plurality of ballastless track of passenger dedicated line are used a lot of investment costs higher foundation reinforcement measures. However, with the line opening and operation, a large number of long-term observation data of the settlement data show that the actual settlement value is significantly smaller than the calculated value. So it is very important to master the characteristics of foundation soil settlement and optimize the foundation treatment, so as to avoid a large amount of engineering waste. Red clay, as a kind of special soil with special engineering properties, has appeared in many railway subgrade projects. The to appear in large numbers in the Shanghai-Kunming high-speed railway of Yunnan section of the mileage for the red clay DK1156-DK1164 section subgrade project as the research object, combined with the specific situation of its inherent special engineering properties, mileage test section, combined with traditional settlement curve prediction quasi legitimate, Flac3D numerical simulation software, to study in the test section of the red clay as natural foundation, composite foundation of CFG pile compression and settlement characteristics. The main research contents and methods of this paper are as follows:1. To collect the test section in engineering geological data, including lithology, geomorphological characteristics, combined with field drilling data, transient surface wave method and electric sounding method of red clay covering layer analysis; in the test section subgrade engineering of foundation soil treatment and situation.2. To do test for the red clay indoor of the test section, to determine of physical and mechanical parameters, analysis its resilience, compression and preconsolidation pressure and other characteristics.3. To do the long-term observation (settlement plate method) for the representative test section about subgrade engineering foundation settlement, the analysis of the characteristics of the foundation settlement; By using three point correction index curve method, hyperbolic method and Asaoka method (Qian’gang method), the settlement observation data are fitted by curve fitting to do the settlement prediction.4. combined with the test section of the engineering geological conditions, using Flac3D finite difference numerical simulation software of natural foundation, CFG pile composite foundation settlement characteristics of research, analysis of the natural foundation of red clay in cutting excavation, Embankment CoMPaction in layers and red clay of CFG pile composite foundation under the different situation of laying out piles exhibit differential settlement.5. On the basis of the analysis of the research results, under the condition of satisfying the high-speed railway subgrade design requirements and for the purpose of to save construction costs,reducing unnecessary waste, discussesing the necessity of test section subgrade red clay foundation actual processing, provideding for reference and guidance for similar projects in the future.