新沂城区超密砂层预制桩桩端阻力的取值探讨

DISCUSSION ON THE VALUE OF PILE TIP RESISTANCE OF PREFABRICATED PILEIN SUPER-DENSE SAND LAYER IN XINYI DISTRICT

新沂城区埋深16~23 m范围内分布的超密砂层,地区预制桩桩基参数通常按建筑桩基技术规范经验法取值,一般也不进行破坏性试桩静载检测,桩基设计布桩偏密加剧了工程桩沉桩困难、桩身上涌、基桩阻力损失等桩基施工问题。基于静载试验,通过对该超密砂层单桩极限端阻力qpk的反分析,初步给出了该超密砂层qpk的取值区间,为地区该超密砂层作为预制桩桩端持力层时的桩基参数建议及桩基优化设计提供一定的借鉴。

The super-dense sand layer is distributed in the buried depth of 16~23 m in the Xinyi district.The parameters of the prefabricated pile foundation are usually taken according to the empirical method of the technical code for building pile foundation,and the static load test of the destructive test pile is generally not carried out.The design of the pile foundation is too dense,which aggravates the difficulties of pile sinking,pile upwelling,pile resistance loss and other pile foundation construction problems.Based on the static load test,through the back analysis of the ultimate tip resistance q_(pk) of the single pile in the super dense sand layer,the value interval of q_(pk) of the super-dense sand layer is preliminarily given,which provides some reference for the pile foundation parameter suggestion and pile foundation optimization design when the super-dense sand layer is used as the bearing layer of the prefabricated pile tip.