{"title":"A hybrid nondestructive testing method for detecting cavities behind the retaining wall","authors":"Jung-Doung Yu, Jong Sub Lee, Hyun-Ki Kim","doi":"10.12989/SSS.2021.28.4.567","DOIUrl":null,"url":null,"abstract":"This study proposes a combination of nondestructive testing methods for detecting soil cavities behind retaining walls, which adversely affect the stability of the sloping ground or retaining structures. An experimental study is conducted using a soil chamber filled with dry sands retained by a concrete wall plate. A hemispherical soil cavity is simulated just behind the wall plate, and elastic wave reflections of impacts on the wall are measured using accelerometers. The measured elastic waves are analyzed using the signal energy in time domain and predominant frequency and mobility spectrum in frequency domain. In addition, spatiotemporal changes in the surface of the wall during heating and cooling sequences are monitored using infrared thermography. The captured thermal image is then used for identifying the cavity. Experimental results show that the cavity leads to increases in the signal energy, predominant frequency, and flexibility in the mobility spectrum. The contrasts in the thermal images effectively reveal the shapes and locations of the soil cavity. This study demonstrates that the hybrid testing method that conducts a careful inspection by elastic waves on areas suspected in the preliminary scanning by the infrared thermography can be competitive and effective for detecting soil cavities.","PeriodicalId":51155,"journal":{"name":"Smart Structures and Systems","volume":null,"pages":null},"PeriodicalIF":2.1000,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Smart Structures and Systems","FirstCategoryId":"5","ListUrlMain":"https://doi.org/10.12989/SSS.2021.28.4.567","RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENGINEERING, CIVIL","Score":null,"Total":0}
引用次数: 0
Abstract
This study proposes a combination of nondestructive testing methods for detecting soil cavities behind retaining walls, which adversely affect the stability of the sloping ground or retaining structures. An experimental study is conducted using a soil chamber filled with dry sands retained by a concrete wall plate. A hemispherical soil cavity is simulated just behind the wall plate, and elastic wave reflections of impacts on the wall are measured using accelerometers. The measured elastic waves are analyzed using the signal energy in time domain and predominant frequency and mobility spectrum in frequency domain. In addition, spatiotemporal changes in the surface of the wall during heating and cooling sequences are monitored using infrared thermography. The captured thermal image is then used for identifying the cavity. Experimental results show that the cavity leads to increases in the signal energy, predominant frequency, and flexibility in the mobility spectrum. The contrasts in the thermal images effectively reveal the shapes and locations of the soil cavity. This study demonstrates that the hybrid testing method that conducts a careful inspection by elastic waves on areas suspected in the preliminary scanning by the infrared thermography can be competitive and effective for detecting soil cavities.
期刊介绍:
An International Journal of Mechatronics, Sensors, Monitoring, Control, Diagnosis, and Management airns at providing a major publication channel for researchers in the general area of smart structures and systems. Typical subjects considered by the journal include:
Sensors/Actuators(Materials/devices/ informatics/networking)
Structural Health Monitoring and Control
Diagnosis/Prognosis
Life Cycle Engineering(planning/design/ maintenance/renewal)
and related areas.