STUDY OF CHANNEL DEFORMATION AT BRIDGE CROSSING SECTIONS OF GEORESOURCES TRANSPORTATION SYSTEMS
| Autor: | Arestak A. Sarukhanyan, Pargev O. Baldjyan |
|---|---|
| Jazyk: | ruština |
| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | Известия Томского политехнического университета: Инжиниринг георесурсов, Vol 332, Iss 5, Pp 148-155 (2021) |
| Druh dokumentu: | article |
| ISSN: | 24131830 2500-1019 2413-1830 |
| DOI: | 10.18799/24131830/2021/5/3194 |
| Popis: | The relevance of the study is conditioned by the necessity of achieving an uninterrupted and reliable operation of systems associated with the transportation of georesources. An important component of the engineering structures of these systems are bridge crossings. On the streams of the mountain zone, these crossings are often performed single-span. In the transition sections for establishing the bridge supports, the width of the river narrows, which leads to erosion of the bottom soil. The mark of the sole of the support and the very conditions of its long-term operation, depends on the accuracy of determining the maximum amount of erosion of the bottom of the river. From this point of view the problem under consideration is topical and will follow a solution that is of important practical value. The main aim of the work is modelling of channel transformations processes running at bridge crossing sections in mountain foothill zones and developing a calculation method for determining riverbeds deformations. The objects of the present study are initial parameters of the stream and channel characteristics of waterways in mountain foothill zones, hydrodynamic processes occurring at the bridge crossing section in rivers of a mountain foothill zone; channel deformations of the bottom; boundary conditions of the problem and the shape of the cross section of the channel. Methods. As a result of a relatively complete analysis of existing works the current state of the set problem has been assessed and the ways of development were marked; physical and theoretical modeling of the channel transformation at the bridge crossing area was performed; boundary conditions for various structural solutions of bridge crossings were determined; a method for hydraulic calculation of channel transformations at bridge crossings was developed for streams of mountain-foothills; numerical example was calculated according to the developed methods and the obtained results were analysed. Results. The paper introduces the physical model of the final stable stage of channel transformations at the bridge crossing section. The hydrological, hydraulic and channel parameters that are initial in solving the problem are identified. A mathematical model of nonuniform flow motion in the conditions of the transformed river bottom of the transition section was compiled taking into consideration equations of energy, continuity of flow and sediment balance. At the same time, the problem in view is aimed at establishing such a position of the bridge crossing bottom when the channel erosion will come to the end and the steady-state flow – restored. In elaborations boundary and boundary conditions of the problem were established. Dependences of the transverse form of the channel and the Shezy formula were also used. As a result of joint solutions of the above expressions a calculation method was developed to establish the position of the stabilized bottom on the transitional section of the river and hydraulic parameters of the flow. A numerical example of calculation made for determining the coordinates of the stabilized bottom and free surface in a bridge crossing is presented. The estimation of calculation results is given. The authors have made a conclusion on possibility of using the proposed method in calculations of parameters of transitional sections of mountain-foothill rivers. |
| Databáze: | Directory of Open Access Journals |
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