EXPERIMENTAL STUDY OF BEARING BEHAVIOUR OF COMPOSITE FOUNDATION WITH RAMMED SOIL-CEMENT TAPERED PILES

Aiming to composite foundation with rammed cement-soil piles in soft ground,the contrast tests for a group of composite foundation with 9 rammed cylindrical cement-soil piles and three groups of composite foundation with 9 rammed tapered cement-soil piles are performed in laboratory,respectively.The relationships of average settlement-load and average pile-soil stress ratio-load,and the load transferring law of four groups of composite foundations with rammed cement-soil piles under the same condition are studied.The test results indicate that:(1) The differential settlement between pile and soil can be adjusted by rammed tapered cement-soil pile;and the ground settlement can be decreased and its bearing capacity can be enhanced obviously.(2) The bearing behaviour of rammed tapered cement-soil piles in the composite foundation can be exerted by enhancing its taper.The average pile-soil stress ratio of composite foundation with rammed tapered cement-soil piles is higher than that of composite foundation with rammed cylindrical cement-soil piles.(3) With the increase of the taper,the decay rate of axial force in rammed cement-soil tapered pile is increased and the load transferring depth is reduced.The bearing characteristic of rammed tapered cement-soil pile is better than that of rammed cylindrical cement-soil pile.The taper is bigger,the pile properties can be exerted more fully.