A study of the shear mechanical properties of high-filled gravel-block soil after dynamic compaction near the Jiangbei airport

The high-filled slopes near the Chongqing Jiangbei Airport are generally 60-120 m high, and the fill is mainly the sand-mudstone mixture, with high stone content and large-size block stone. Exploratory pits were excavated to 4 m deep to measure the density and composition of the fill and get the scene images. Combining grading test with image processing technology was carried out, and the whole grading curve of the fill was obtained. From the engineering scale, the gravel-block soil with the size less than 60 mm after dynamic compaction was taken as the soil particles in the numerical simulation. The shear properties of the soil were tested with the direct shear test with the remolded samples. Based on the photo analysis, numerical models of large-scale particle flow of fill were set up. The grained stones’ actual distribution was considered in the numerical test. The shear behavior, damage evolution and shear strength of the fill in near the Jiangbei Airport were simulated. The results show the fluctuation characteristics of shear stress and normal displacement when the fill reaches and exceeds the peak value. The effects of large stone and stone content on the shear band bifurcation and post-peak shear stress dropping are also discussed.