Study On The Constrcution Quality Of Cfg Piles On The Railway Passenger-only Transportation

CFG pile composite foundation bond strength pile is a representative of the composite foundation. It had been widely used in the construction of multi-storey buildings in the 1980's. In the 1990's, it was used for the reinforcement of soft foundation. So far, it has been extensively used in the foundation reinforcement of high-rise and super high-rise buildings. With the coming of upsurge in the construction of railway passenger-only lines, the CFG piles and the construction technology of cushion composite foundation has been widely used in the special lines. However, problems of lack of experiences still exist when the CFG pile is applied to the soft railway foundation treatment, the control of key projects, the construction quality, and the quality control, especially the application of the piling construction method by a long spiral drill pipe mixture infusion through pump pressure. There has been no special State-issued specification so far yet except some local standards. So, this method is still under test due to complicated construction technology and demanding quality.In the present work, the Wuhan-Guangzhou railway passenger-only line, a key project in which the CFG pile was mainly used in the soft foundation treatment, was taken into consideration to investigate the reinforcement mechanism. The reason why the CFG pile technology was applied in the line was analyzed. The Wuhan-Guangzhou model of the CFG pile composite foundation was initiated. Meanwhile, the DK1713+536.18～1820+029.65 segment in the Wuhan-Guangzhou railway passenger-only line was chosen as a study object to analyze the CFG pile construction technology by a long auger drill hole pumping mixture and to discuss the common quality problems and quality control methods. Common problems of pipe blocks, II and III types of piles, and channeling holes were discussed through the QC method when the CFG pile technology was adopted. In the end, the first successful application of the CFG pile on the cutting slope of the railway passenger-only line was analyzed to sum up the reinforcement principle, characteristics, construction methods, and application results. Thus, references are provided for the soft foundation treatment and reinforcement of cutting slopes in the railway works through the CFG pile technology.