The changes of engineering-geological conditions occurring during the construction and operation of buildings and structures are considered. Engineering-geological surveys and studies to justify repair and reconstruction projects, which must take into account such changes, is a separate section of engineering geology.

The strength of clay rocks is largely determined by their water content and the ratio of its various categories. At present, most authors consider the types of water categories in terms of their formation under the influence of the energy field of the clay particle. It is known that the strength of any energy field decreases according to the law close to exponential, so the tRASsition of water from one category to another is gradual and smooth. When imposing a particle field on water, its structure is distorted due to changes in the nature of tRASslational motion of water molecules.