The use of Rayleigh waves in the geotechnical characterization of soils in an unstable hillside area in the city of Ubatuba/SP

• Grant number: 06/00852-3
• Support Opportunities: Regular Research Grants
• Start date: June 01, 2006
• End date: May 31, 2008
• Field of knowledge: Engineering - Civil Engineering - Geotechnical Engineering
• Principal Investigator: Renato Luiz Prado
• Grantee: Renato Luiz Prado
• Host Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

This proposal aim to study the dispersion curve of Rayleigh waves to back-calculating the shear wave velocity profile (VS) starting from a multichannel acquisition as in the conventional seismic reflection survey. It will be implemented the MASW technique (multichannel analysis of surface waves). From the values of VS and the densities of the investigated materials, it will be obtained the curves of variation of the dynamic shear moduli with the depthThe research also has another important objective: to compare the results obtained in different periods (dry and wet seasons) in a hillside area (subject to slipping) with unsaturated soils in the city of Ubatuba, São Paulo state, place of countless mass movements. The hypothesis for the development of this research starts from the question: if the strength of unsaturated is, among other factors, govern by the negative pressure of the intersticial water, could the periodic monitoring of the Rayleigh waves, and the consequent subsurface profile of the dynamic shear moduli (G0), to serve as subsidy for the evaluation of the stability of the hillsides?The survey will be done in a test area in Ubatuba, already object of other geophysical and geotechnical investigations in the ambit of the projects FAPESP 03/07182-5 and 05/55736. (AU)