Effectiveness of Lime Treatment of Coarse Soils Against Internal Erosion

The construction of embankments and other earth hydraulic structures using coarse soils requires assessing their potential for internal erosion by suffusion, defined as detachment and transport of fine particles through the matrix constrictions under internal flow. For potentially erodible coarse soils containing a certain amount of clays, a possible remedial solution is the lime treatment which is studied in this work in an experimental program consisting in: erosion test, crumb test, unconfined compression test and microstructure characterization tests (SEM, mercury intrusion porosity). The experiments were carried out on a reconstituted soil owing similar characteristics to natural coarse soils. The treatment reported in this study is carried out using a minimum lime content of only 1%, which can be achieved in situ in a cost-effective manner. Comparisons of results on treated and untreated soils showed that the lime treatment is effective after only 24h of treatment. The suffusion is stopped, the agglomeration of the particles generated by the treatment seems to be maintained after samples immersion and the unconfined compressive strength (UCS) is improved. The microstructure observations of the fine part of the soil (particles smaller than 1mm) showed the appearance of agglomerates generating an increase of the pore volume.