Dynamic stress properties of dynamic compaction (DC) in a red-sandstone soil–rock mixture embankment

The characteristics of dynamic stress and displacement are investigated in this study with laboratory and field tests of dynamic compaction (DC) in a red-sandstone soil–rock mixture embankment. Under four different DC energies (i.e., 1200, 1080, 960, and 840 kN m), the properties of the vertical and horizontal displacement and the dynamic stress contours at different depths induced by DC are obtained in an on-site test. The test results indicate that the effective reinforcement depth and range are approximately 4.0–6.0 and 3.0–4.0 m, respectively. When the dynamic stress in the contours is greater than 10 kPa, the dynamic stress attenuates dramatically. The regression analysis method is adopted to obtain the control equations and the parameters of settlement and dynamic stress attenuation. Based on settlement and dynamic stress data fitting method, the fitting parameters are obtained. The dimensionless analysis method is used for obtaining the design approach of the effective reinforcement depth and range for the red-sandstone soil–rock mixture embankment. The proposed design approaches are applied to the construction program of the Changji Expressway in Hunan, China. By means of long-term settlement observation of DC section K212 + 475 and ordinary section K180 + 655, the effectiveness of the red-sandstone soil–rock mixture embankment in the DC section K212 + 475 is 534.78% greater than that of the ordinary section K180 + 655, which demonstrates that the designed calculation equation and formulae are practicable.