Multichannel analysis of surface waves on concave concrete structures : numerical model and experimental validation

Abstract : In this paper the propagation of surfaces waves is investigated in the case of seismic measurements recorded along the circumference of concave structures. The underlying objective is to recover non destructively the mechanical properties of material from multiple channel analysis of surface waves measurements. This experimental configuration along the circumference is unavoidable in the case of concrete circular tunnels or shafts when the sensors cannot be installed along the structure base line. For surface waves it is shown that the influence of the curvature has a major impact on its phase velocity which cannot be incorporated in classical multiple channel analysis of surface waves forward problem. Consequently, we have developed a numerical model dedicated to such geometry that relies on complex values of the surface waves phase velocity. This model is confronted with experimental data recorded on a reduced scale concrete tunnel of metric size. The agreement between experimental and numerical shall be the basis of an in situ non destructive testing technique