大直径超长摩擦灌注桩在深圳地区应用研究  

Application and research of large-diameter and super-long friction bored piles in Shenzhen

作　　者：张伟[1] 王兴法[1] 刘俊[1] 严力军[1] 赵洋[1] 

机构地区：[1]香港华艺设计顾问(深圳)有限公司,深圳518031

出　　处：《建筑结构》2013年第23期92-99,共8页Building Structure

摘　　要：基于深圳后海片区场地地质情况存在桩基持力层埋深较深、强风化层桩周土的摩擦力特征值较高的特点,对比分析超高层建筑采用大直径超长摩擦灌注桩的可行性。计算分析表明:较小直径基桩承载力由桩身强度控制,较大直径基桩承载力由桩岩土层承载力特征值控制。考虑不同区域场地土层分布的差异性,1,2号塔楼、裙房部分桩端持力层分别选择强风化层下段、中风化层和强风化层上段,各区域持力层有所区分,做到经济合理。对塔楼和部分裙房基桩采用桩端后注浆技术,能起到加固桩底沉渣、弥补泥浆护壁施工工艺不足造成的桩端阻力损失等问题。结合现有检测手段和试验能力,提出利用试验桩进行静载荷试验,并通过在桩身内预埋钢管,解决超长桩桩底钻芯取样困难的问题。针对此类型地质情况的桩基设计和施工经验可为深圳后海片区同类型工程提供参考。Based on the characteristics of super-deep bearing layer and high characteristic value of skin friction in highly weathered rock under geological conditions in Houhai areas of Shenzhen, the rationality of application of large-diameter and super-long friction bored piles was analyzed by comparison analysis of super-tall buildings. The computational results show that the bearing capacities of small-diameter and large-diameter piles are controlled respectively by pile strength and skin friction. Considering the difference of soil layer distribution in different areas, the bearing layers for pile-end are chosen as respectively lower segment, middle-weathered layer and superior segment of highly weathered layer for 1,2 towers and podium to save cost. The technique of post-grouting at the pile-end was adopted in towers and part of podium, which can reinforce sediment at pile-end and compensate for stress loss of pile-end due to insufficient construction technology at shaft wall protection by drilling mud. Combining the existing examination method and test capacity, it is proposed to carry out static loading test for test piles and embed steel pipes in piles, which can solve the problem of core-pulling for sampling of super-long piles. The experience of design and construction is provided for reference for this type of geological conditions in Houhai areas of Shenzhen.

关 键 词：大直径超长摩擦灌注桩 静载试验 桩身强度 单桩承载力特征值 

分 类 号：TU473.14[建筑科学—结构工程]