An Optimal Design Procedure of Wave Barriers for Mitigation of Underground and Above-Ground Railway Vibrations

In this paper, a robust parallel finite-element/genetic-algorithm (FE/GA) procedure is presented for finding the optimal layout of wave barriers in the ground alongside the underground or above-ground railways. The proposed FE/GA procedure is capable of optimizing the topology of the wave barriers by altering the FE model geometry and mesh at each optimization step to cope with the excitations by underground, above-ground, and simultaneous under- and above-ground loadings. The results obtained show that this coupled procedure is effective for the analysis and design of different types of wave barriers subjected to dynamic transient loadings. Three different types of wave barriers are studied including wave impeding blocks (WIBs), jet-grouted columns, and trenches. It is found that the open trenches have the largest mitigation capacity and if they cannot be used, the WIBs perform better than the jet-grouted columns. Although the wave barriers can notably reduce the ground vibrations induced by underground trains, they perform more effectively when the source of vibrations is located at the ground surface.