Deformation Property of Sensitivity Silt under Different Loading and Unloading Paths

During the construction of the first terrace in the middle reaches of Fenhe River in Shanxi Province, it is found that the saturated silt foundation will have a great additional settlement after being disturbed, and it will not be stable for a long time, showing sensitivity. Based on one-dimensional consolidation creep test, the deformation characteristics of sensitive silt under different loading and unloading paths were studied in this paper. The results show that the loading and unloading path and loading and unloading ratio are important factors affecting the compression curve. The stress corresponding to the turning point of the compression curve is the structural yield stress. The larger the loading ratio is, the larger the settlement, coefficient of consolidation, coefficient of secondary consolidation and primary consolidation ratio under the same loading level increase, and the compression curve becomes more linear and the characteristic turning point disappears, however, the higher the loading ratio, the shorter the construction period. The magnitude of preloading and unloading rate will affect the rebound of sensitive silt. When the preload is greater than the yield stress of the structure, the greater the unloading ratio, the greater the amount of rebound, so it is necessary to take the stepwise unloading method to reduce the amount of rebound to ensure the preloading effect. When the target load is less than the yield stress of the structure, the effect of surcharge preloading method to reduce the post-construction settlement is significant.