GPR time-spectral analysis of metallic, plastic and concrete targets

• Grant number: 16/22978-0
• Support type: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): January 01, 2017
• Effective date (End): December 31, 2017
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geophysics
• Principal researcher: Vinicius Rafael Neris dos Santos
• Grantee: Túlio Cordeiro Bicudo
• Home Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The field of subsoil structures evaluation has been increased with the large engineering ventures, making necessary to carry out such task in a fast and preferably non-destructive way. In 2003, a test site was installed on the campus of USP consisting of metallic, plastic and concrete targets which are subjected to weather like heavy rains, drought and high temperatures, which may cause some type of damage on the materials. Such changes may be imperceptible when analyzed with the GPR (Ground Penetrating Radar) method in the time domain, but when performing a time-frequency analysis, some changes on the interaction between the electromagnetic wave and the material can be determined, indicating possible damages with time, such as oxidation, mechanical deformation, cracking or even leakages. Thus, the objective of this project is to perform a spectral analysis of the traces and radargrams using spectral density, short-time Fourier transform and Wigner-Ville distribution in metallic and plastic drums and pipes and concrete tubes in the frequencies of 200 and 400 MHz, over these 13 years of the IAG/USP test site installation. The data to be used were acquired during the years of 2004, 2005, 2007, 2009, 2013, 2014, 2015, 2016 and 2017, during periods of rain and drought. This type of estimation is extremely important because it is a non-destructive evaluation that can be performed in urban environments to engineering, environmental and structural evaluation. (AU)