Abstract
The article describes the problems of construction and design of irrigation and drainage structures on loess subsidence when soaking soils. Irrigation and drainage structures are widely used for laying canals, dams and other water facilities. The difference between these structures from industrial and civil is that water is soaked at the base of irrigation and drainage structures over a very large area. Moreover, depending on the properties of subsidence soils and the thickness of the layer at the base of the structure, subsidence can range from several centimeters to several meters. A large number of accidents were recorded during the design and construction of such structures in natural conditions on the territory of the Republic of Uzbekistan, Kazakhstan, Tajikistan, the Republic of the North Caucasus and in the south of Ukraine, where subsidence loess soils occupy a large area and extend for 10 meters. The article motivates the necessary laboratory and field studies of soils at the stage of research and design. Methods of research on experimental sites are described in detail and the results of the research are presented. It has been established that large subsidence deformations at the base of irrigation and drainage structures begin from a certain depth, which depends on the results of laboratory studies of the characteristics of subsidence properties. The conclusions of the article indicate various factors that determine the occurrence of emergencies at irrigation and drainage facilities and how to predict the operation of such facilities in time, taking into account the results of laboratory and field studies.