An update on techniques to assess normal-mode behavior of rock arches by ambient vibrations
An update on techniques to assess normal-mode behavior of rock arches by ambient vibrations
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DOI：
10.5194/esurf-9-1441-2021
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发表时间：
2021-11
影响因子：
3.4
通讯作者：
M. Häusler;Paul R. Geimer;R. Finnegan;D. Fäh;Jeffrey Ralston Moore
中科院分区：
文献类型：
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作者：
M. Häusler;Paul R. Geimer;R. Finnegan;D. Fäh;Jeffrey Ralston Moore
抽象的。天然岩拱是一种罕见而美丽的地质地貌，具有重要的文化价值。因此，其管理需要定期评估结构完整性，以了解环境和人为因素对拱稳定性的影响。被动地震振动的测量代表了一种快速和非侵入性的技术来描述自然拱的动态特性，包括共振频率，模态阻尼比和模态振型，可以随着时间的推移进行监测，用于结构健康评估。然而，通常应用的频谱分析工具往往是有限的，在他们的能力，以解决密集或复杂的高阶模式的特性。因此，我们调查了两种技术，以及建立在土木工程领域通过应用到一组自然拱门，其特征在于使用偏振分析和光谱峰值拾取技术。从增强的频域分解和参数协方差驱动的随机子空间识别模态分析的结果表明，一般良好的协议与频谱峰值拾取和频率相关的极化分析。然而，我们表明，这些先进的技术提供了解决紧密间隔的模式，包括其相应的模态阻尼比的能力。此外，由于相位信息的保存，增强的频域分解允许直接和方便的三维可视化的模式形状。这些技术提供了详细的表征动态参数，可以监测，以检测结构的变化，表明损坏和故障，此外，有可能改善用于拱稳定性评估的数值模型。我们的研究结果鼓励广泛采用和应用这些先进的模态分析技术的动态分析范围广泛的地质特征。
Abstract. Natural rock arches are rare and beautiful geologic landforms with important cultural value. As such, their management requires periodic assessment of structural integrity to understand environmental and anthropogenic influences on arch stability. Measurements of passive seismic vibrations represent a rapid and non-invasive technique to describe the dynamic properties of natural arches, including resonant frequencies, modal damping ratios, and mode shapes, which can be monitored over time for structural health assessment. However, commonly applied spectral analysis tools are often limited in their ability to resolve characteristics of closely spaced or complex higher-order modes. Therefore, we investigate two techniques well-established in the field of civil engineering through application to a set of natural arches previously characterized using polarization analysis and spectral peak-picking techniques. Results from enhanced frequency domain decomposition and parametric covariance-driven stochastic subspace identification modal analyses showed generally good agreement with spectral peak-picking and frequency-dependent polarization analyses. However, we show that these advanced techniques offer the capability to resolve closely spaced modes including their corresponding modal damping ratios. In addition, due to preservation of phase information, enhanced frequency domain decomposition allows for direct and convenient three-dimensional visualization of mode shapes. These techniques provide detailed characterization of dynamic parameters, which can be monitored to detect structural changes indicating damage and failure, and in addition have the potential to improve numerical models used for arch stability assessment. Results of our study encourage broad adoption and application of these advanced modal analysis techniques for dynamic analysis of a wide range of geological features.