Health status identification of modular-block-reinforced soil retaining walls after earthquakes

Distribution of dynamic characteristics (natural frequency and damping ratio) of large-scale shaking table model tests on a reinforced soil retaining wall (RSRW) under different working conditions is analyzed by using the time-domain identification method. The variation characteristics of dynamic characteristics at different positions of the RSRW are introduced, and the distribution laws of its dynamic characteristics under different damage degrees are expounded. The quantitative relationship between the amplitude of dynamic characteristics and the damage degree of the RSRW is explored. The results show that at the early stage of loading stage, the natural frequencies are basically the same, and the damping ratio decreases with the increase of wall height. At the later stage of loading, the natural frequency of the RSRW decreases obviously, and the damping ratio increases greatly. The distribution curves of the natural frequency and damping ratio are obtained by the mathematical methods. The variation amplitudes of the natural frequency and damping ratio are obtained for the following four stages: basic intact, slight damage, moderate damage and destruction. When the decrease amplitude of the natural frequency is 6.75 % ~ 16.43 % and the increase amplitude of the damping ratio is 106.14 % ~ 243.09 %, it can be considered that the RSRW is at the middle failure stage. When the decreasing amplitude of the natural vibration frequency is 16.43 % ~ 31.59 % and the increasing amplitude of the damping ratio is 243.09 % ~ 462.04%, it can be considered that the RSRW is at the destruction stage.