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Field Validation of Effective Dispersion Analysis of Reflections, a New Method for Nondestructive Estimation of Pile Depth
Transportation Research Record: Journal of the Transportation Research Board ( IF 1.7 ) Pub Date : 2021-04-26 , DOI: 10.1177/03611981211008186
Vivek Samu 1 , Murthy Guddati 1
Affiliation  

Several methods have been developed for nondestructive pile depth estimation over the past few decades, with impact-based methods remaining popular because of their ease of application. Sonic-echo techniques rely on generating nondispersive longitudinal waves by impacting the pile top and subsequently picking peaks that correspond to initial and reflected wave arrivals. Unfortunately, pile tops are often inaccessible for in-service foundations and alternate impacting techniques result in signals for which time domain peak picking can be difficult. Pile sides are often easily accessible, but side impact generates highly dispersive flexural waves resulting in complicated waveforms for which analysis is not straightforward. Existing methods to process dispersive flexural waves rely on signal processing based methods and do not explicitly incorporate the physical dispersion properties of the system, resulting in large errors. To address the current limitations, a new method called effective dispersion analysis of reflections (EDAR) was recently developed for pile length estimation. EDAR provides a simple and robust technique to analyze dispersive flexural waves generated from side impact for which time domain processing is not applicable. In this paper, length estimation through EDAR is explained for longitudinal and flexural waves using synthetic bar and Timoshenko beam models. Field validation for two types of pile, concrete filled steel tubes and prestressed concrete, with varying cross sections and embedment are presented. EDAR resulted in pile length estimates within 10% error.



中文翻译:

反射有效色散分析的现场验证,一种桩深无损估算的新方法

在过去的几十年中,已经开发出了几种用于无损桩深估计的方法,基于冲击的方法由于易于应用而仍然很受欢迎。声波回波技术依靠撞击桩顶并随后拾取与初始波和反射波到达相对应的峰值来生成非分散纵波。不幸的是,使用中的基础通常无法接近桩顶,并且替代性的冲击技术导致信号难以时域峰值拾取。桩的侧面通常很容易接近,但是侧面碰撞会产生高度分散的弯曲波,从而导致复杂的波形,而对其进行分析并不简单。现有的处理色散弯曲波的方法依赖于基于信号处理的方法,并且没有明确地合并系统的物理色散特性,从而导致较大的误差。为了解决当前的局限性,最近开发了一种称为有效反射色散分析(EDAR)的新方法来估计桩长。EDAR提供了一种简单而强大的技术来分析因侧面冲击而产生的色散弯曲波,而时域处理不适用于该弯曲波。在本文中,解释了使用合成棒和Timoshenko光束模型通过EDAR对纵向波和挠曲波进行的长度估计。提出了两种类型的桩的现场验证,钢管桩是钢管混凝土还是预应力混凝土,具有不同的横截面和埋入方式。

更新日期:2021-04-27
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