Development of the underground erosion of the soils adjoining the concrete constructions (on the example of Zagorsk pumped storage power plant, ZPSPP-2)

The matter of such a dangerous geological process as suffosion is briefly considered in the article. Some examples of destruction and removal of the suffusion unstable breeds on the contact with the concrete structure are given. Sone cases of vertical (downward and upward) and sloping streams in relation to a concrete construction are considered. It is proved that after the formation of the primary underground channel the suffosion process passes into the erosive one. This transition is smoothly and gradual, hidden from the immediate observation. However, the erosive process development leads to the repeated increase in the intensity of the incoherent soil destruction. In case of existence of soil removal zone, not only the large underground channel is formed, but also large cavities in the zone of contact of the concrete structure and the soil massif are formed. It quite often leads to the emergency situations. Studied the example of the Zagorsk PSPP-2 (ZPSPP-2). The development of the erosive process under the ZPSPP-2 building led to the formation of large cavities (up to 10 m) and to the general subsidence of the building of the plant and of the retaining wall 3 (RW3) on 1.17 m down.