Analysis of acoustic emission patterns for monitoring of rock slope deformation mechanisms
Analysis of acoustic emission patterns for monitoring of rock slope deformation mechanisms
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DOI：
10.1016/j.enggeo.2016.11.021
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发表时间：
2017-03-09
影响因子：
7.4
通讯作者：
Marcato, Gianluca
中科院分区：
文献类型：
--
作者：
Codeglia, Daniela;Dixon, Neil;Marcato, Gianluca
声发射（AE）是土体和岩石材料在位移过程中粒子的重排或崩塌前微观结构损伤的增加而产生的；因此声发射是估算边坡退化的合适方法。为了克服地质材料的高衰减特性，从而能够监测声发射活动，开发了一种利用波导将声发射波从变形区传输到压电换能器的系统。该系统将声波活动量化为响铃计数（RDC）率。在土壤应用中，RDC速率与变形速率相关，而最近在岩石边坡上的应用需要新的解释策略。为了制定新的战略，在意大利和奥地利的两个岩石边坡试验点安装了该系统。对这些地点分别在5年和1.5年测量的RDC率进行了分析，并确定了明确和反复出现的趋势。将声发射趋势与现场可用的一系列传统仪器的响应进行比较，可以与外部边坡荷载和内应力变化的变化相关联。意大利大型岩质边坡的声发射特征已被确定为响应地下水位和雪荷载的变化而产生的。在奥地利的斜坡上，声发射信号包括冬季连续冻融循环导致的小巨石从斜坡表面脱落。本文所报道的工作有助于岩质边坡声发射监测和解释策略的发展。长期目标是确定即将发生的破坏，并推导出设定阈值的规则，这些阈值可用于及时发出岩质边坡破坏警告，以便采取行动。(C) 2016 Elsevier B.V.版权所有
Acoustic emission (AE) is generated in soil and rock materials by rearrangement of particles during displacement or increasing damage in the microstructure preceding a collapse; therefore AE is appropriate for estimation of slope degradation. To overcome the high attenuation that characterise geological materials and thus to be able to monitor AE activity, a system that makes use of a waveguide to transmit AE waves from a deforming zone to a piezoelectric transducer was developed. The system quantifies acoustic activity as Ring Down Count (RDC) rates. In soil applications RDC rates have been correlated with the rate of deformation, whereas the recent application to rock slopes requires new interpretation strategies. In order to develop new strategies the system was installed at two rock slope trial sites in Italy and Austria. RDC rates from these sites, which have been measured over 5 and 1.5 years respectively, are analysed and clear and recurring trends are identified. The comparison of AE trends with response from a series of traditional instruments available at the sites allows correlation with changes in external slope loading and internal stress changes. AE signatures from the large rock slope in Italy have been identified as generated in response to variations in the groundwater level and snow loading. At the slope in Austria, AE signatures include the detachment of small boulders from the slope surface caused by the succession of freeze-thaw cycles during winter time. The work reported in this paper is contributing to the development of AE monitoring and interpretation strategies for rock slopes. The longer-term aim is to identify approaching failures and derive rules for setting thresholds that can be used to give warning of rock slope failures in time to enable action to be taken. (C) 2016 Elsevier B.V. All rights reserved.