针对软土地基中的夯实水泥土桩复合地基,分别进行1组圆柱形桩和3组不同楔角楔形桩的9桩复合地基对比试验,研究这4组复合地基在相同条件下的桩－土平均沉降差、桩体应力、平均桩－土应力比、平均沉降随荷载变化的规律.研究结果表明: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:在一定荷载范围内,夯实水泥土楔形桩复合地基的平均桩一土应力比夯实水泥土圆柱形桩复合地基的平均桩一土应力比大:随着荷载的增加,桩体所分担的荷载是有限的,夯实水泥土楔形桩复合地基的平均桩－土应力增长趋于稳定或下降,即楔形桩的倾斜侧壁能有效地缓解桩体应力集中现象.%Aimed at composite foundation with rammed cement-soil piles in soft ground, the contrast tests on a group of composite foundation with nine rammed cylindrical cement-soil piles and three groups of composite foundation with nine rammed tapered cement-soil piles were performed in laboratory, respectively. The average settlement difference among pile and soil, pile stress, average pile-soil stress ratio and the relationship between load and average settlement of four groups of composite foundation with rammed cement-soil piles were respectively studied under the same condition. The results indicate that the differential settlement between pile and soil can be adjusted by rammed tapered cement-soil pile, the ground settlement decreases and its bearing capacity is enhanced obviously. The bearing behavior of rammed tapered cement-soil piles in the composite foundation can be exerted by enhancing its taper. Within some load scopes, 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. With the increase of load unceasingly, the load shared by tapered piles increases restrictedly, and the average pile-soil stress ratio of composite foundation with rammed cement-soil tapered piles is near a certain value or falls down, i.e. the slope skin of tapered pile can effectively alleviate the stress concentration of pile.
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