An energy flow study of a double-deck tunnel under quasi-static and harmonic excitations

This paper presents a comparison between the vibration energy flow radiated by a double-deck tunnel and the one radiated by a simple tunnel when both are excited by constant or by harmonic moving loads. For both cases, the radiated energy is computed using a three-dimensional semi-analytical model of the system. The total energy radiated upwards is presented for a wide range of load speeds, when a constant moving load is considered, and for a wide range of excitation frequencies, when the excitation is a harmonic moving load. Significant differences have been obtained, first, for constant loads moving at very high speeds and, second, for harmonic loads moving at typical speeds for underground trains. •The response of a double-deck tunnel is compared with the response of a simple tunnel.•An energy flow comparison method is proposed.•The comparison for constant moving loads shows differences only at very high speeds.•The comparison for harmonic moving loads shows significant differences.