New horizons in practical liquefaction prediction and mitigation measures for existing structures

Abstract

The paper presents some recent research advances on practical liquefaction prediction and mitigation measures for existing structures. A new simplified generalized liquefaction prediction and assessment method that is capable of considering the influence of the waveforms and durations of earthquakes has been developed. The validity of this method adopting the effective number of waves concept has been comprehensively verified using the case histories of past major earthquakes for the cases of liquefaction and no liquefaction. A unique feature of the new simplified method is its universality, allowing it to be applied to all types of liquefaction charts based on SPT N-values, CPT q-values, and shear-wave velocities. The paper also presents a new compaction grouting that can reduce the ground upheaval quantity, which has remained an issue for more than 50 years, by 80–90%. The new compaction grouting, up-and-down method, has substantially higher efficiency of upheaval/uplift control and higher efficacy as liquefaction countermeasures around existing structures.