A model for the erosion of fine particles due to groundwater pumping and induced surface settlements

The pumping of groundwater from drainage wells is often used in urban environment as a short-term provision to temporarily lower the water table level. The possible consequences of the erosion of fine particles from the soil surrounding the well are discussed, first in terms of local variations of volume and mechanical characteristics of the soil, subsequently in terms of the induced surface settlements. To this pur- pose, some laboratory tests are first presented, aimed at investigating the erosion from soil samples subjected to a seepage flow. The modelling of the processes of erosion and transport of the fine particles is then at- tempted through a numerical approach, based on a suitable law of erosion and on the conservation of mass of the moving particles. The procedure, calibrated on the basis of the laboratory tests, is subsequently adopted for the evaluation of settlements in an actual case.