Experimental study on long-term dynamic strength of gravel soil under traffic loading

Abstract

In order to maintain the long-term dynamic stability of gravel soil subgrade under traffic loading and prevent fatigue damage, it is necessary to determine the long-term dynamic strength of gravel soil under different working conditions. The dynamic triaxial test was carried out on the 40 groups of remolded gravel soil samples under chosen 8 working conditions. Based on the results of the dynamic triaxial test, the εp-N curves and εp-lgN curves were drawn. Further, the σd-lgNf curves of gravel soil were drawn, and finally, the long-term dynamic strength computation model of gravel soil was established. The effects of confining pressure, water content, degree of compaction, loading frequency, and initial static deviatory stress on the long-term dynamic strength of gravel soil were also analyzed. It is concluded that With the increase of confining pressure and compaction degree, the long-term dynamic strength of increases. With the increase of the number of loading cycles and initial static deviatory stress, the long-term dynamic strength decreases. At the optimal water content, the long-term dynamic strength is the highest. And the impact of loading frequency on the long-term dynamic strength is relatively small. The relationship between the long-term dynamic strength under 1 ×106，5 × 106 and 1 ×107 loading cycles of gravel soil and the resilient modulus was established, and the value of the relationship curve coefficient ranges from 0.885 to 1.945.