This project involves building and demonstrating a wireless seismic system for assessing the condition of railroad ballast.The system is designed for portability and ease of use by non-specialized personnel. It is based on the well-known multi-channel analysis of surface waves (MASW) method. The system consists of a seismic source and an array of receivers. The source will be empirically optimized for use in ballast inspection, and can be configured for generating Rayleigh waves or Love waves. The system software will provide real-time data analysis without requiring specialized user training. Sensor data is transferred wirelessly to a tablet computer which generates dispersion curves (i.e., propagation velocity versus frequency), and a modeling and inversion routine creates a shear velocity depth profile that is consistent with the dispersions curve. The resulting shear velocity depth profile indicates the condition of the ballast and its capacity to support rail traffic. Field tests with the instrument will be conducted on revenue track where the ballast condition has previously been measured and monitored, with the goal of using the shear velocity profile to assess and predict ballast performance.
