This paper investigates the influences that steel type, in situ soil properties, water table depth, pile diameter, roughness and driving procedures have on the ageing behaviour of piles driven in sand. Tension tests have been performed on 51 open-ended steel micro-piles, with 48 to 60 mm outside diameter, driven at well-established research sites at Larvik in Norway, Dunkirk in France and Blessington in Ireland to better understand the processes that control axial capacity set-up trends in the field. Mild steel, stainless and galvanised steel micro-piles were driven and left to age undisturbed for periods of between 2 h and 696 days before being subjected to first-time axial tension load tests. In addition to reporting and interpreting these experiments, further investigations of the sites’ geotechnical profiles are reported, including new piezocone and seismic cone penetration soundings as well as laboratory tests. Integration with earlier ageing studies at the same sites with larger (340 to 508 mm outside diameter) open-ended steel piles driven to 7 to 20 m embedments and experiments that varied the piles’ initial surface roughness shows that corrosion, pile scale, roughness, the bonding of soil particles and the driving process can all be highly significant. New insights are gained into the mechanisms that control the axial capacity of piles driven in sand.

中文翻译：

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在三个地点进行野外实验，以研究年龄对砂土打入钢桩的影响

本文研究了钢的类型，原位土壤特性，地下水位深度，桩直径，粗糙度和打桩程序对打砂桩的老化行为的影响。已在挪威拉尔维克，法国敦刻尔克和爱尔兰布莱辛顿等著名研究基地对51个外径为48至60毫米的开放式微型钢桩进行了拉力测试，以更好地了解控制轴向的过程。该领域的能力设置趋势。驱动低碳钢，不锈钢和镀锌钢微型桩，使其不受干扰地老化2小时至696天，然后进行首次轴向拉伸载荷测试。除了报告和解释这些实验外，还报告了对该场地岩土剖面的进一步调查，包括新的压电锥和地震锥穿透测深以及实验室测试。与在较大位置（外径为340至508 mm）的端部开放式钢桩打入7至20 m嵌入物的同一地点的早期老化研究相结合，并通过改变桩的初始表面粗糙度的实验表明，腐蚀，桩垢，粗糙度，土壤颗粒的结合和驱动过程都非常重要。控制沙子的桩的轴向承载力的机制获得了新的见识。桩的结垢，粗糙度，土壤颗粒的粘结以及打桩过程都非常重要。控制沙子的桩的轴向承载力的机制获得了新的见识。桩的结垢，粗糙度，土壤颗粒的粘结以及打桩过程都非常重要。控制沙子的桩的轴向承载力的机制获得了新的见识。