扩缩径对灌注桩承载性能的影响研究

Study on the Influence of Expanding and Shrinking Diameter on Bearing Performance of Cast-in-place Pile

文中以广东某超高层建筑项目为例,通过PLAXIS软件建立有限元模型,就扩缩径对灌注桩沉降量以及桩身应力的影响进行分析。结果表明,各土层下荷载-沉降曲线表现为先快速增加后缓慢增加,淤泥土层桩的极限竖向位移量为0.046 87 mm,与正常桩相比降低了4.3%;粉质黏土层扩径桩的极限竖向位移量为0.042 43 mm,与正常桩相比降低了12.6%。土层对缩径桩的极限竖向位移量影响不大;淤泥粉质黏土层扩径桩的极限竖向位移量为0.043 26 mm,与淤泥层条件下的极限沉降量相比降低了9.8%。桩扩径部位应力值降低;缩径位置应力值显著增加,因此,应对桩缩径处进行加固处理。

Taking a super high-rise building project in Guangdong as an example,the finite element model was established by PLAXIS software to analyze the influence of expanding and shrinking diameter on the settlement amount and pile stress.The results show that the load-settlement curve under each soil layer increases rapidly at first and then slowly.The ultimate vertical displacement of pile in silt soil layer is 0.046 87 mm,which is 4.3% lower than that of normal pile.The ultimate vertical displacement of the enlarged pile in silty clay layer is 0.042 43 mm,which is reduced by 12.6% compared with normal pile.Soil layer has little effect on the ultimate vertical displacement of reduced pile.The ultimate vertical displacement of enlarged pile in silty clay layer is 0.043 26 mm,which is 9.8% lower than that in silt layer.The stress value of the expanding part of pile decreases;The stress value at the reduced diameter of pile increases significantly,so the reduced diameter of pile should be strengthened.