Efficient and economic foundations are essential to ensure the long-term integrity of structures. Driven ductile piles offer a safe and quick solution for foundations, which can be individually customized to changing soil conditions. Geotechnical load tests on a small subset of piles can be performed at large construction sites to examine the bearing capacity for optimization purposes. Arising deformations during these statical tests are usually measured using electrical sensors at the top, which, however, do not deliver information about the stress distribution along the pile. This paper presents a fiber optic monitoring approach, which provides distributed strain profiles with a spatial resolution of up to 10 mm along driven ductile piles. The high measurement resolution of about \(1~{\mu}m/m\) enables the detection of local effects in the load transfer from the pile to the surrounding grout and soil. The critical sensor installation on-site as well as results of various field applications with pile lengths of up to 25 m are presented. Verification measurements at the pile’s head and internal measurements of strain gauges prove the suitability of the developed monitoring approach and demonstrate the high potential of distributed fiber optic sensing for applications in soil mechanics.

中文翻译：

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沿驱动球墨铸铁桩进行分布式光纤传感：设计，传感器安装和监控的好处

高效和经济的基础对于确保结构的长期完整性至关重要。打入式延性桩为地基提供了一种安全，快速的解决方案，可以针对各种土壤条件进行个性化定制。可以在大型建筑工地上对一小部分桩进行岩土工程荷载测试，以检查承载力，以达到优化目的。通常在顶部使用电传感器来测量这些静态测试过程中引起的变形，但是，该传感器不会传递有关沿桩身应力分布的信息。本文提出了一种光纤监测方法，该方法可沿驱动的延性桩提供分布的应变剖面，其空间分辨率最高可达10 mm。约\（1〜{\ mu} m / m \）的高测量分辨率能够检测从桩到周围灌浆和土壤的载荷传递中的局部影响。介绍了现场关键传感器的安装以及桩长最高达25 m的各种现场应用的结果。桩头的验证测量和应变仪的内部测量证明了开发的监测方法的适用性，并证明了分布式光纤传感技术在土壤力学中的巨大潜力。