Since the layered soilbags is a congeries of individual soilbags

the discontinuous surface between the soilbags has the effect to reduce and absorb the vibration energy when it is used as foundation for low-rise building. However

the dynamic behaviour between soilbag interface was rarely studied so far. Using the large-scale direct shearing apparatus

the cyclic shearing tests were conducted on the soilbag interface and pure natural sand

and the variations of the shear stress

vertical displacement

dynamic shear stiffness

and equivalent damping ratio with shear displacement were compared. In addition

the interfacial frictional behaviour between the upper and lower soilbags was discussed. The results show that the initial shear stiffness

peak shear stress

and strain softening behaviour for soilbag interface are reduced compared to those of pure natural sand

but the shear stress-displacement loop is larger. The skeleton curve of soilbag interface can be better described using the Kondner-Zelasko model. For soilbag interface

an obvious contractive deformation is observed during cyclic shearing

while the dilatation is only observed under the low vertical stress and large shear displacement. The total contraction increases with increasing vertical stress

cyclic number and shear amplitude

and the change of vertical displacement within each cycle is smaller than that of pure natural sand. Additionally

the dynamic shear stiffness of soilbag interface is smaller than pure nature sand

but the equivalent damping ratio becomes larger

which indicates the advantage of soilbag structures to reduce vibration.