3D performance of a seepage control wall in dam and foundation

This article analyzes the results of numerical modeling of the stress-strain state (SSS) of a grout curtain carried out by the cut-off wall method in the dam foundation and body of the Yumaguza hydroelectric complex. On the river channel section the wall cuts through not only the riverbed deposits, but also the lower part of the dam. On the right-bank section the wall cuts through only the upper part of a very thick layer of clay soils. The numerical model parameters of the structure and the foundation were selected in a way allowing to obtain approximate conformance of field and calculation data on the settlements of the gallery located beneath the wall. It was revealed during model calibration that the uplift of the gallery recorded from the field data is related to the reservoir filling. At the rise of the groundwater level a part of the soil mass in the dam foundation and body passes into a suspended state. The main type of wall deformations was presented by deformations due to vertical compression from settlements of the surrounding soil. These deformations result in the concentration of compressive stresses in the wall. The non-uniform distribution of settlements along the dam site causes bending deformations in the wall plane. This longitudinal bend results in small tensile stresses appearing in the wall in the direction along the dam site. However, on the whole, the wall SSS is rather good because it is compressed from all sides. Bending deformations of the wall due to its bend are negligible.