Test study on the influences of dynamic stress and load history to the dynamic properties of the remolded red clay

The dynamic properties of subgrade materials are critical factors affecting stability within the traffic engineering discipline. Remolded red clays are frequently used as subgrade filling materials, however, to date, a paucity of data exist on to the dynamic properties of this material. Accordingly, a large number of dynamic triaxial tests under cyclic loads were carried out to quantify the suitability of remolded red clay as subgrade filling. Several potentially influencing dynamic factors were considered, including dynamic stress, vibration frequency, consolidation confining pressure, consolidation ratio and compactness. Plastic strain and dynamic strength curves of remolded red clays under varying dynamic loads and load histories have been developed, in addition to the inclusion of those influencing factors. Test results show that within the range not exceeding the inherent strength of the test samples, increases soil compactness, confining pressure, and vibration frequency serve to enhance overall dynamic power in concurrence with retarding the development of accumulated plastic strain. Conversely, an improvement in the amplitude of the dynamic stress and consolidation ratio was shown to cause a decrease in dynamic strength and acceleration in the development of accumulated plastic strain. An empirical equation relating critical dynamic strength and load histories of remolded red clay has been developed for the provision of fundamental reference data for future studies.