Field experiments and numerical analysis on the ground vibration isolation of wave impeding block under horizontal and rocking coupled excitations

In this paper, the effectiveness of a semi-analytical BEM in studying the vibration mitigation of wave impeding block (WIB) in layered soil under horizontal loads is verified by field tests, subsequently the performance of WIB in mitigating the vibrations of ground subjected to horizontal-rocking excitations were investigated by numerical analysis using the verified BEM. Two types of layered half-space model under the horizontal-rocking excitations (site A: the stiff soil ground with relatively soft overlying soil layer, site B: the soft soil ground with relatively stiff overlying soil layer) are considered. Test and numerical results indicate that WIB can achieve desired vibration isolation effectiveness in layered soils under both the horizontal and horizontal-rocking coupled excitations. With the decrease of the embedded depth, the performance of WIB for vibration mitigation improves in layered ground under horizontal excitation. For horizontal-rocking coupled excitation, WIB reduces ground vibration by 50-70% at zones over one diameter of WIB (10 m) away from the vibration source; at zones within one diameter of WIB, peak A(R) value occurs, and the peak values are beyond 1.0 (2.0 in site A and 12.5 in site B at normalized distance D = 0.75) in radial direction. WIB behaves generally better in site A than in site B.