Experimental Study on Vertical Bearing Capacity and Cyclic Compression Behavior of Soilbags

Soilbags have been successfully applied to the reinforcement of building foundation with obvious effect on seismic isolation, but their deformation characteristics under dynamic load have not been studied in depth yet. In order to further analyze the vertical bearing capacity and deformation characteristics of soilbags, a series of laboratory unconfined ultimate loading tests and cyclic compression tests were conducted, and the effect of the number of loading cycles, the static load, and the cyclic load ratio on the dynamic characteristics of soilbags was studied in terms of the vertical stress-strain variation and the dynamic compression modulus. The test results show that with the increase of the number of layers, the ultimate strength of stacked soilbags decreased gradually and tended to a stable value of 0.7 MPa, and the peak compression modulus also decreased and stabilized at 6.73 MPa. An obvious plastic deformation of stacked soilbags was observed at the beginning of the cyclic compression test, and the vertical residual strain generated in each cycle decreased gradually and tended to zero with the increase of the number of cycles. The dynamic compression modulus was basically stable throughout the whole testing process, and was not affected by the number of cyclic loads. With the increase of the upper static load, the dynamic compression modulus of the stacked soilbags increased gradually. After 200 cycles of loading, the dynamic compression modulus of soilbags with the static load of 50 kN reached 53.87 MPa. However, it significantly decreased with the increased cyclic load ratio. When the cyclic load ratio was 0.4, the dynamic compression modulus of soilbags could still reached 49.39 MPa after 200 cycles of loading. In general, under the action of vertical dynamic load, the soilbags can satisfy the requirements of bearing capacity and stability as a kind of seismic isolation material.