超深水泥土桩质量检测方法和控制标准

通过分析现行规范中水泥土桩各种质量检测方法的不足,重点阐述了单桩和复合地基载荷试验因受荷载作用面积和时间的限制,影响深度浅,不能反映大面积、长期荷载作用的实际工程受力状况。然后研究了现场桩身水泥土质量特性和影响因素,提出水泥土桩的质量检测应以现场标贯试验为主要手段：通过钻孔取芯观察定性判断水泥土搅拌的均匀性;通过标贯击数定量判断搅拌均匀的水泥土强度,并辅以芯样的室内无侧限抗压强度试验。最后,提出了搅拌均匀的水泥土桩质量合格标准为10d龄期的标贯击数不低于10击。

EVALUATING METHODS AND STANDARDS OF EFFECTIVENESS ON CEMENT DEEP MIXING PILE

In the paper the evaluating methods of effectiveness on cement deep mixing pile in present specifications are reviewed and their shortcomings , especially those associated with the static loading tests of single pile and composite ground which hare a shallower load transfer both and do not embody the mechanic state of pile Under a large scale and long term load, are discussed . After quality properties and influence factors of in-situ cement-soil are analyzed, Stanedard Penetration Test (SPT) is propose to be the primary evaluating method for the to mixing pile: the homogeneity of cement-soil can be inspected by the samples drilled from the pile shaft, the strength can be achieved by the SPT counts for homogeneous cement-soil, as well as the unconfined compression tests of the cement-soil samples. Finally, the quality standards of homogenous deep mixing pile are suggested that N63.5 is more than 10 counts at 10 day ages.