The effect of physical-chemical and chemical factors on peculiarities of swell and osmotic shrinkage of clay provided to unmembrane’s effect is analyzed. It is demonstrate that the genesis of swell due to water inflow in soil and its outflow is principally different and depends on different correlation of clay pore water concentration (Сп) and solutions filter-passing (Сф). The balance equations for five types of swells are adduced. The experimental researches are allowed to obtain the equation for calculation of solution concentration (boundary of osmotic shrinkage Споу). The exceeding of Споу leads to osmotic shrinkage of clay formation. The conclusion of strength and deformation capacity of clay by swell and shrinkage is gained.