Virtual inversion of environment vibration sources caused by rail traffic in urban areas

摘要

The environment vibration source of rail traffic has been dealt with by many researchers, mainly by railway spectra from observation of the vibration. From the 3D point of view, the real source function can never be observed, even though seismometers are installed at points very close to the railway, since the observation must be mixed with the vibration from many other sources along the way. In order to validate the possibility of inversing the source function from ground observation, a virtual inversion is presented in this paper. The vertical displacement time histories at an array from a series of triangular pulses are synthesized to simulate the impacts of wheels and rail joints while a train goes through the railway. The cross power spectra are calculated from the displacements at each two points of the array, and are taken as the objective functions to inverse the intensity and the duration of the source function by means of the micro-Genetic algorithm. The inversion result is quite close to the given values, and provides a good foundation for further study on inversion of random vibration source function.