Study on dynamic characteristics of salinized silt under cyclic loading.

ABSTRACT

Under the repeated action of aircraft taxiing load, the subgrade plastic deformation becomes the key factor affecting the service performance of the airfields when salinized silt is used to fill the subgrade. In this study, the dynamic triaxial tests were carried out on a region in the northern part of China to study the effects of different salt contents on the dynamic characteristics of silt under cyclic loading. A prediction model for the salinized silt dynamic strength with a plastic strain of 4% as the failure criterion for the subgrade was thus proposed. It is found that with the increase of dynamic stress amplitude, the salinized silt plastic deformation transforms gradually from plastic deformation to incremental failure. The salt contents significantly influence the plastic strain and critical dynamic stress of silt. The strength of the salinized silt specimen is related to the ion concentration in the soil pores and the arrangement pattern of soil particles, as indicated by the progressive strength increase of the salinized silt at the low salt content of 1% and a further gradual decrease at high salt content.