摘要
采用自平衡试桩法获得了广佛肇高速公路3根大直径嵌岩桩的荷载-位移曲线,并等效转换为传统静载荷试验的荷载-位移曲线,分析了3根试桩的荷载传递规律以及单桩极限承载力的构成,并将极限端阻力和极限侧阻力与经验计算方法进行了对比分析。结果表明:三根试桩的等效Q-s曲线均为缓变型,无明显拐点,试桩处在弹性压缩阶段,承载力设计值较为保守,安全储备大;桩顶在极限加载条件下,端阻力和侧阻力近似相等且均得到较好的发挥;中风化岩层对嵌岩桩的侧摩阻力提升效应明显,而当桩端进入微风化岩层时侧摩阻力变化不大,且桩端阻力没有显著的提升,故当中风化岩层能提供足够的极限承载力,则嵌岩桩桩端可不进入微风化岩带,从而有效节省工程造价。
The load-displacement curves of three large diameter rock-socketed piles in the Guangfozhao Expressway were obtained by self-balanced static loading test method,and equivalently converted into load-displacement curves of traditional static load test. The law of load transfer of three testing piles and the composition of the ultimate bearing capacity of the individual pile were analyzed,and the ultimate tip resistance and the ultimate side resistance were compared with the empirical calculation methods. The results indicates that：（ 1） The equivalent Q-s curves of the three testing piles are changing slowly,without obvious inflection point,and all the testing piles are in the elastic compression stage. The design value of bearing capacity is conservative and the reserve of safety is enough;（ 2） Under the limit loading condition,the tip resistance and the side resistance are approximately equal and both are well mobilized;（ 3） The middle-weathered rock layer has obvious enhancement on the side friction resistance of the rock-socketed pile,whereas when the pile tip enters the micro-weathered rock layer,the side friction resistance does not change much and the pile tip resistance does not increase significantly. Therefore,if the weathered rock layer can provide enough ultimate bearing capacity,the rock-socketed pile tip doesn＇t need to be socketed into the micro-weathered rock layer,thus effectively save the project costs.
作者
夏兼
徐福建
XIA Jian;XU Fujian(Guangdong Provincial Chang Da Highway Engineering Co.,Ltd.,Guangzhou,Guangdong 510620,China;Nanjing Dong Da Self-balance Pile Test Co.,Ltd.,Nanjing,Jiangsu 210018,China)
出处
《水利与建筑工程学报》
2018年第5期57-61,共5页
Journal of Water Resources and Architectural Engineering
关键词
自平衡静载试验
极限承载力
端阻力
侧摩阻力
self-balanced static loading test
ultimate bearing capacity
tip resistance
side frictional resistance
