Subsidences and erosion in loess soils

The properties of loesses are very peculiar. The formation of loess is stable in the dry state, but under the effect of moisture it could present great subsidence. Sometimes in loess some processes are in progress. Similar to karst formation in the water-soluble rocks, but chiefly connected with mechanical suffosion (loess pseudokarst). In the water saturated condition loess soils are of a lower bearing capacity. Locally the loess is characterized by some self-progressing processes of underflooding by underground waters. Provoked by earthquakes and explosions some thixotropical liquefaction of loess soils may occur. All these processes have drawn the attention of researchers, engineers and agronomists of different countries to loess. In the first part of this paper we consider the collapse deformations and wash-outs of loess (Savvateev 1974), in the second part — pseudokarst processes (Kriger; Lavrusevich; Petrov 1983).