Evaluation of post liquefaction settlement and treatment and reinforcement of the soil by stone columns

During earthquakes, the shear strength and bearing capacity of saturated sandy soils decreases; this is related to an increase in pore pressure. In the ultimate state, the pore pressure becomes equal to the initial effective stress, at which time the material loses all its resistance and liquefaction occurs. Thus, the prediction of the post-liquefaction settlement of the soil is an important step to reduce the seismic risk. Several methods have been developed for the prediction of Seismic-Induced Settlement, the most widely used is that based on the results of in-situ tests SPT, and Several soil reinforcement techniques can be considered, the choice depends mainly on the grain size of the soil to be treated. This article presents a comparative study of the methods for evaluating Seismic-Induced Settlement based on the experimental results of the in situ SPT tests, applied to an earthquake-prone area in northern Morocco which had specific soil formations characterized by the existence of layers of sand over several meters, which suggests the possibility of soil liquefaction and proposes a method of reducing the risk of liquefaction. The analysis of existing SPT data leads to interesting conclusions both in terms of the comparative analysis of methods for the prediction of the post-liquefaction settlement and the understanding of the effect of Soil treatments by Stone Columns to mitigate the risk of liquefaction.