夯实水泥土楔形桩复合地基承载特性试验研究

 针对软土地基中的夯实水泥土桩复合地基，分别进行1组等截面桩和3组不同楔角楔形桩的9桩复合地基对比试验，研究4组复合地基在相同条件下的平均沉降和平均桩–土应力比随荷载变化的规律以及荷载传递规律。试验结果表明：夯实水泥土楔形桩能有效地调节桩–土沉降差和地基沉降，提高地基承载力；增大楔形桩的楔角能使桩体较早地发挥其承载性能，夯实水泥土楔形桩复合地基的平均桩–土应力比较夯实水泥土等截面桩复合地基的大；随侧壁倾角的增大，夯实水泥土楔形桩桩身轴力的衰减速率不断增大，随荷载传递深度不断减小，楔形桩的工作性状远优于等截面，且侧壁倾角越大，桩体的性状能得到较好地发挥。

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.