Unscented hybrid simulated annealing for fast inversion of tunnel seismic waves

A new hybridized global optimization method that combines simulated annealing global search with unscented Kalman filter minimization is proposed to solve waveform inversion for predicting ahead of the underground tunnel face. The authors demonstrate in this work fast and reliable convergence of this new algorithm through validation of optimization of a multi-minima test function and inversion of synthetic tunnel seismic waveforms to predict the geological structure ahead of the tunnel face. With regard to the engineering application, the successful identification of the true model by minimizing a multimodal misfit functional for wide feasible bounds of the model parameters confirms that waveform inversion by the improved global optimization method is promising for practical applications with real measurement data.