Research progress and frontier scientific problems in loess dynamics

The research progress of loess dynamics, the train of their thoughts and the deficiency of the existing results are summarized. Based on the relative requirements of quantification and theorization of loess dynamics, the frontier scientific problems in researches on loess dynamics in the future are put forward. The results show that the reality of saturated-loess liquefaction and unsaturated-loess seismic subsidence is not doubtful. For the existing researches, the dynamic triaxial test in laboratory is the main approach to investigate loess dynamics. Based on the laboratory data, more attention is paid to influences of three aspects, i.e., physical properties of loess, microstructural characteristics of soil, and types of dynamic loadings. Almost all researches fail to consider the physical process and mechanical mechanism of dynamic behaviors of loess, and thus both the quantification and the theorization are relatively weak. According to the review and analysis, it is believed that the future frontier scientific problems in loess dynamics should include five aspects: quantitative description of loading effect caused by ground motion on loess, dynamic responding mechanism of loess based on micro interaction of three phases of solid, water and air, quantitative relationship between dynamic response of solid-phase and macro structure strength of loess, coupling influence of earthquake and rainfall on dynamic responding of loess mass, and probability-based assessment of dynamic hazard risk of loess mass.