There is described a method of consolidating foundation soils and/or building sites in general, which comprises injections of expanding chemical products which are projected and carried out by means of monitoring the effects which are progressively measured in the soil in the course of treatment by means of sequential tomographies of the electrical resistivity. Those consolidating injections will be carried out until the percentage variation of the electrical resistivity Δρ(%), measured in quasi-real time in the soil being treated and always with respect to the initial condition before the injection will not constitute sequential gradients (Nth) which differ from the preceding one (N−1) for variations contained in the range ±5%.