<p>The article is devoted to experimental research of the major dynamic indicator of soil. The study describes the technique for conducting research on vibrating installation. There are marked changes in the adhesion of moist forest masses depending on density – humidity of soil, intensity, duration and parameteкs of dynamic effects. The possible values of soil adhesion in a dry, moist and water-saturated conditions have been analysed. The research results contribute to the appointment of the protective measures, the prevention of seismic subsidence deformations of the constructions that cannot be obtained with weak soils during strong earthquakes.</p>