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Abstract To validate the working mechanism of reinforced embankment supported by cast-in-situ thin-wall tubular piles，field test has been performed in a highway section from Jiujiang to Xiaotang around Guangzhou City. Test results show that tubular pile has a large vertical bearing capacity，and punching failure happens to most piles in static tests. Moreover，the bearing capacity of single tubular pile composite foundation is also large with small settlements. Tests still suggest that soil arching effect and tension membrane effect are the two key factors influencing the load transfer mechanism. The pile-soil stress ratio varies with the embankment loads and differential settlements between piles and soil. The total settlement of tubular pile composite foundation under embankment load is small. Differential settlements are found between soil above pile cap and soil among piles，respectively，and increase of this difference can reflect the degree of soil arching effect. In addition，excess pore water pressure，which is induced by embankment loads，turns up slightly and decreases rapidly along depth. It is nearly zero at the depth of 6.0 m. The lateral deformation of embankment is small，and decreases rapidly along depth；and it reaches its peak value at the depths of 3.0 to 4.5 m.
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Received: 06 April 2010
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2010, Vol. 29 
