In recent years, there has been a focus on improving geotechnical systems by implementing and constructing new deep foundation such as helical and expanded piles. This study examined the effects of parameters such as embedment depth, pile geometry, and axial loading direction on the load-displacement behaviour of these piles. To conduct the research, a database was compiled consisting of 80 axial loading test records for different piles. The embedment depth of the piles ranged from 2.4 to 36.8 m, and the diameter of helices or expanded parts ranged from 254 to 1500 mm. The ultimate load of the piles was determined using the 2.5% and 5% displacement ratio criteria and the Brinch-Hansen 80% method. Additionally, hyperbolic functions were fitted to the load-displacement curves, allowing for consistent estimation of the limit load and the initial tangent modulus. Analysis of the results from the database revealed that the dominant factors influencing the ultimate load, limit load, maximum measured load, initial stiffness, and load-displacement behaviour were the ratio of helices or expanded part diameter to shaft diameter, shaft and toe surface area, and load direction. Correlations derived from the database were validated using measurements from eight full-scale helical and expanded piles.

中文翻译：

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螺旋桩和扩孔桩的双曲载荷-位移分析：数据库方法

近年来，人们一直致力于通过实施和建造螺旋桩和扩孔桩等新的深基础来改善岩土系统。本研究研究了埋深、桩几何形状和轴向载荷方向等参数对这些桩的载荷-位移行为的影响。为了进行这项研究，我们编制了一个数据库，其中包含不同桩的 80 条轴向载荷测试记录。桩的埋置深度为2.4至36.8 m，螺旋或扩口直径为254至1500 mm。桩的极限荷载是使用 2.5% 和 5% 位移比标准和 Brinch-Hansen 80% 方法确定的。此外，将双曲函数拟合到载荷-位移曲线上，从而可以对极限载荷和初始切线模量进行一致的估计。对数据库结果的分析表明，影响极限载荷、极限载荷、最大测量载荷、初始刚度和载荷位移行为的主要因素是螺旋或扩张部分直径与轴直径、轴和趾部表面积的比率和载荷方向。使用八个全尺寸螺旋桩和扩张桩的测量结果验证了从数据库中得出的相关性。