This paper deals specifically with the improvement, on land, of soft silty clay and highly organic silty clay through the addition of cementing agents, by means of dry mixing. Lime and different type of cement have been employed and the improvement measures on cylindrical laboratory-mixed specimens has been followed up for a certain period of time. It has been found that blast furnace cements work rather well for both soil type. In the field, instrumented trial embankments built both on improved and on non-improved ground have put on view the benefit of different binder dosages with L-C columns installed. Moreover, the actual improvement on site of the soil columns and the effects of the column installation on the soil nearby have been assessed by field testing.