Test on the Influence of Geometric Parameters of an Annular Trench on the Vibration Isolation Area

Table 1

Physical index of the back-filled sand.

Index	Apparent density (kg/m^3)	Bulk density (kg/m^3)	Porosity (%)	Mud content (%)	Fineness modulus
Value	2621.8	1571.3	37.1	0.67	3.15