"Вестник МГСУ"

The estimation of changes in the ecological situation and bottom topography in the Ob Bay, which may be caused by the construction of the approach channel to the port of Sabetta, was carried out with the help of the developed complex of numerical models. Particular attention was paid to the study of the displacement of the boundaries of the saline water expansion and the sediment accumulation in the channel area. It is established that the possible influence of the approach channel on the hydrologic-hydrochemical characteristics is less than their natural interannual and seasonal variability in the investigated water area. The change in the bottom topography after the construction of the approach channel does not entail a significant change in the regime of hydrologic-hydrochemical parameters of the Ob Bay and, consequently, should not affect the biocenosis. The calculated changes in the bottom topography in the approach channel area will not exceed 2 % of the depth per year and will not become a significant obstacle to the reliable and uninterrupted operation of the Sabetta port.

There are considered the results of stress-strain state analysis of polymer diaphragm in the body of the 50 m high earthfill cofferdam of Gibe III dam. The diaphragm is made of polyvinylchloride (PVC) geomembrane and has a zigzag location. Computations were conducted with the finite element method. A thin geomembrane was modeled by rod-shaped finite elements. Computations showed that the diaphragm made of geomembrane is a sufficiently safe seepage-control element: there are small tensile stresses on its individual sections. The geomembrane damage may occur in it only in the part anchored to the upstream shell. Considerable tensile stresses appear in anchors which are comparable with the geomembrane tensile strength. If the geomembrane is made of PVC, there will be a margin of safety. It is not recommended to anchor the diaphragm into the upstream shell but make it only into the downstream shell.

The article presents the research of MGSU Corporation for testing of design solutions of the “Eastern petrochemical company” JSC oil refinery and petrochemical plants port complex using the physical modeling method. Construction of the marine terminal of the oil refinery and petrochemical plants port complex is planned to be on the Eastern shore of the Vostok Bay which is the part of Peter the Great Bay in the Sea of Japan. The port area is created by means of an artificial land site. The water area of the terminal will be guarded against sea waves by a breakwater. Experiments on the study of wave propagation in the port model water area at the Eastern and Western breakwaters were performed in the laboratory wave basin in three-dimensional layout, with the aim of obtaining of data about wave heights at berthing facilities. Effectiveness of the breakwater designs was studied in two-dimensional layout in a wave flume. During the port model construction all the designed waterworks as well as the project bathymetry of the port water area were reproduced at a scale of 1:100. Analysis of the experiment results with the slope protection embodiment version demonstrates that this engineering solution is able to withstand waves of the design parameters.

There was studied the stress-strain state of 215 m high rockfill dam where the seepage-control element is presented by a reinforced concrete face of soil-cement concrete placed on the under-face zone. Calculations were carried out for two possible variants of deformability of rock outline taking into account the non-linearity of its deformative properties. It was obtained that the reinforced concrete face and the soil-cement concrete under-face zone work jointly as a single construction - a double-layer face. As the face assembly resting on rock is made with a sliding joint the scheme of its static operation is similar to the that of the beam operation on the elastic foundation. At that, the upstream surface of the double-layer face is in the compressed zone and lower one is in the tensile zone. This protects the face against cracking on the upstream surface but threatens with structural failure of soil-cement concrete. In order to avoid appearance of cracks in soil-cement concrete part due to tension it is necessary to achieve proper compaction of rockfill and arrange transverse joints in the double-layer face.

The article deals with technique of creation and results of calculations of the three-dimensional geofiltrational model of the Rogun HPP construction site. When performing works on creation of the Rogun HPP three-dimensional geofiltration model, geological and hydrogeological conditions of the Rogun HPP construction site were analyzed. They showed that the construction site consists mostly of fractured rocks of various weathering degrees. In terms of preservation, four preservation zones were identified in the rock mass. These zones define the features of hydrogeological conditions that have emerged in the area of construction. Calculation results illustrated the absence of seepage areas on the lower slope of dam; this is the indication of normal operation of the dam impervious circuit. The drainage system of the underground hydropower plant has a high efficiency. Operation of the drainage galleries complex leads to a significant reduction of piezometric pressure on roofs of the machine and transformer halls. Above the underground structures a completely drained area is formed. Completed forecast calculations on geofiltration model of the Rogun hydropower plant determine the hydrostatic pressure and piezometric pressure at any point of the modeled area. These data can be used as loads while designing of lining of underground workings.

The article focuses on the assessment of stress-strain state of soil mass of dock-type lock chamber. Numerical modeling of the soil mass of dock-type lock chamber with a continuous bottom is performed. The soil model was selected, and calculation of stress-strain state of the lock chamber soil mass was performed applying the PLAXIS 2D programming and computing suite. In the process of the structure stress-strain state analysis the assessment of its state in conditions of filling-emptying of the lock chamber was performed. To assess the possibility of reducing the load of the backfill soil and pore pressure on the lock chamber wall, the article discusses the simulation of excavation of upper part of the lock chamber backfill; also, the possibility of replacing of clay soil filling by sandy soil filling is considered. A numerical modeling results verification with field observations materials obtained during operation of the facility was performed according to the results of calculations of horizontal and vertical shifts of the facility. The study demonstrated a satisfactory convergence of the results of calculations performed in the Plaxis programming and computing suite with the field observations materials. Presented calculation results show that the replacement of upper part of backfill soil without combining with other structural measures can not duly change the load from the soil on the chamber wall, nor its stress state.