-
Bautdinov Damir Tahirovich -
Russian State Agrarian University - Moscow Timiryazev Agricultural Academy (RSAU - MTAA or RSAU - MAA named after K.A. Timiryazev)
Candidate of Technical Sciences, Associate Professor, Department of Technical Mechanics and Construction, Russian State Agrarian University - Moscow Timiryazev Agricultural Academy (RSAU - MTAA or RSAU - MAA named after K.A. Timiryazev), 49 Timiryazevskaya str., Moscow, 127550, Russian Federation.
-
Atabiev Umar Ishakovich -
Russian State Agrarian University - Moscow Timiryazev Agricultural Academy (RSAU - MTAA or RSAU - MAA named after K.A. Timiryazev)
Postgraduate, Department of Hydro-technical Construction, Russian State Agrarian University - Moscow Timiryazev Agricultural Academy (RSAU - MTAA or RSAU - MAA named after K.A. Timiryazev), 49 Timiryazevskaya str., Moscow, 127550, Russian Federation.
The parametric analysis of the stress state of a transversally isotropic rock mass near a pressurized hydraulic tunnel of a box-shaped form is carried out. Pressurized hydro-technical tunnels of box-shaped cross-section are widely used in the field of hydraulic engineering construction and are one of the complex, labor-intensive and expensive types of structures that make up the main structures of waterworks, melioration systems and water supply systems. As a culvert and water supply facilities they are built underground if the open excavation is impossible or not economical, or when the tunnel runs through a densely populated or densely built-up area, or when landslides, screes, rockfalls are possible. Violation of integrity of the rock mass, in particular, caused by tunneling, modifies the stress-strain state (SSS) of the rock mass, which leads to appearance of tensile stresses in some places, and in some cases, to significant compressive stresses. If these stresses exceed the design strengths of rock to tension and compression, respectively, then the collapse of the working roof and buckling of the side walls and the bottom of the tunnel may occur. Subject: analysis of the stress state of transversally isotropic rocks near the pressurized hydraulic tunnel of horseshoe cross-section caused by the internal head of water. Research objectives: determination of real values of circumferential stresses along the development contour. Materials and methods: solution of the problem of plane deformation of the theory of elasticity for a transversely isotropic medium containing tunnel excavation cannot be obtained by analytical methods, and therefore the stress-strain analysis was carried out by the finite element method using the ANSYS software package, MCE. Results: determination of stresses along the development contour, construction of diagrams and graphs showing the effects of the anisotropy conditions and Poisson’s ratio. The tangential stresses along the contour of hydraulic tunnel development for various values of deformation modulus and Poisson’s ratio are determined, which makes it possible to estimate the strength of the rock mass for different tunnel depths. The analysis of a long hydro-technical tunnel, laid in a strong, transversally isotropic rock, is reduced to the problem of plane deformation of the theory of elasticity for a transversely isotropic medium containing tunnel excavation. The size and type of the finite element suitable for analysis were determined in advance based on the solution of the test problem. Conclusions: it is necessary to determine the physical and mechanical properties of rocky soils more accurately, paying special attention to elastic characteristics; calculations should be performed taking into account the anisotropy of elastic properties.
DOI: 10.22227/1997-0935.2017.10.1172-1179
-
Sainov Mikhail Petrovich -
Moscow State University of Civil Engineering (MGSU)
Candidate of Technical Sciences, Associate Professor, Department of Hydraulic Engineering, Moscow State University of Civil Engineering (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation;
This e-mail address is being protected from spambots. You need JavaScript enabled to view it
.
The author considered the results of the numerical studies of stress-strain state of a 100 m high rockfill dam with a reinforced concrete face. In the analysis, the dam construction sequence and loads applied to it were considered; it was assumed that the reinforced concrete face was constructed after filling the dam. The calculations were carried out in the elastic formulation at various moduli of deformation and Poisson’s ratio. It was revealed that at rockfill settlement under the action of hydrostatic pressure the reinforced concrete face not only bends but also is subject to longitudinal force. The development of these forces is connected not only with rockfill shear deformation in horizontal direction. Depending on the value of rockfill Poisson’s ratio these longitudinal forces may be both compressive and tensile. At the Poisson’s ratio exceeding 0.25 the longitudinal forces are tensile, and when it is equal to 0.2 - they are compressive. Evidently these particular longitudinal forces are the course of crack formation in reinforced concrete faces of a number of constructed dams. The indirect confirmation of the development of tensile forces on the face is the fact that actually in all the dams with reinforced concrete face opening of perimeter joint was observed. Thus, in order to provide the strength of reinforced concrete it is important to increase rockfill shear modulus. Only the decrease of stone compressibility (i.e. increase of linear deformation modulus E) will slightly improve the stress state of the face, as the value of E has less effect on settlements and shear of the dam than Poisson’s ratio. High rockfill dams with reinforced concrete face may have a favorable stress state only at narrow site when the face horizontal displacements are inconsiderable and due to the settlements of rockfill in the face the forces are compressive but not tensile longitudinal forces.
DOI: 10.22227/1997-0935.2015.3.69-78
References
- Concrete Face Rockfill Dam: Concepts for Design and Construction. International Commision on Large Dams (ICOLD). 2010, Bulletin 141, 400 p.
- Rockfill Dams with Concrete Facing-State of the Art. International Commision on Large Dams (ICOLD). 1989, Bulletin 70, 117 p.
- Cooke J.B., Sherard J.L. Concrete Face Rockfill Dams — Design, Construction, and Performance: Proceedings of the 2nd Symposium. Detroit, Mich., October 1985. American Society of Civil Engineers (ASCE), New York. 658 p.
- Nichiporovich A.A., Borovoy A.A., editors. Proektirovanie i stroitel’stvo plotin iz mestnykh materialov : po materialam VII i VIII Mezhdunarodnykh kongressov po bol’shim plotinam [Design and Construction of Dams Made of Local Materials (based on the works of the 7th nd 8th International Congresses on Large Dams)]. Moscow, Energiya Publ., 1967, pp. 90—99. (Proektirovanie i stroitel’stvo bol’shikh plotin. Vyp. 3 [Design and Construction of Large Dams. No. 3]). (In Russian)
- Duncan J.M., Chang C.Y. Non-linear Analysis of Stress and Strain in Soils. ASCE Journal of the Soil Mechanics and Foundations Division. 1970, vol. 96, no. 5, pp. 1629—1653.
- Kondner R.L. Hyperbolic Stress-Strain Response. Cohesive Soils. ASCE Journal of Soil Mechanics and Foundation Division. 1963, vol. 89, no. 1, pp. 115—144.
- Radchenko V.G., Glagovskiy V.B., Kassirova N.A., Kurneva E.V., Druzhinin M.A. Sovremennoe nauchnoe obosnovanie stroitel’stva kamennonabrosnykh plotin s zhelezobetonnymi ekranami [Modern Academic Substantiation of Construction of Rockfill Dams Having Reinforced Concrete Faces]. Gidrotekhnicheskoe stroitel’stvo [Hydraulic Engineering]. 2004, no. 3, pp. 2—8. (In Russian)
- He Yu, Shouju Li, Yingxi Liu, Jun Zhang. Non-Linear Analysis of Stress and Strain of Concrete Faced Rockfill Dam for Sequential Impoundment Process. Mathematical and Computational Applications. 2010, vol. 15, no. 5, pp. 796—801.
- Szostak-Chrzanowski A., Massiéra M., Deng N. Concrete Face Rockfill Dams — New Challenges for Monitoring and Analysis. Reports on Geodesy. 2009, no. 2/87, pp. 381—390.
- Mohd Hilton Ahmad. Principal Stresses in Non-Linear Analysis of Bakun Concrete Faced Rockfill Dam. AJSTD. 2008, vol. 25, no. 2, pp. 469—479.
- Özkuzukiran R.S. Settlement Behavior of Concrete Face Rockfill Dams: A Case Study. A thesis Submitted for the degree of Master of Science in Civil Engineering. Middle East Technical University, 2005, 150 p.
- Park Han-Gyu, Seo Min-Woo, Kim Yong-Seong, Lim Heui-Dae. Settlement Behavior Characteristics of CFRD in Construction Period — Case of Daegok Dam. Jour. of the KGS. September 2005, vol. 21, no. 7, pp. 91—105.
- Xu L., Shen Z., Yang F., Gu X. Stress and Deformation Analysis for the Concrete Face Rockfill Dam of Wuyue Pumped Storage Power Station. Earth and Space Conference. 2012, pp. 986—995. DOI: http://dx.doi.org/10.1061/9780784412190.106.
- Qinxi Wu, Huai Yang, Xianjun Han, Xiaozheng Yu. Research on the Method of Relability Analysis of Concrete-Faced Rockfill dam. ICOLD, 2006, vol. 3, pp. 877—890.
- Halil Firat Özel. Compasion of the 2D and 3D Analyses Methods for CFRDS. A thesis submitted for the degree of Master of Science in Civil Engineering. Middle East Technical University, 2012, 93 p.
- Sainov M.P. Osobennosti chislennogo modelirovaniya napryazhenno-deformirovannogo sostoyaniya gruntovykh plotin s tonkimi zhestkimi protivofil’tratsionnymi elementami [Numerical Modeling of the Stress-Strain State of Earth Dams That Have Thin Rigid Seepage Control Elements]. Vestnik MGSU [Proceedings of Moscow State University of Civil Engineering]. 2012, no. 10, pp. 102—108. (In Russian)
- Sainov M.P. Osobennosti raschetov napryazhenno-deformirovannogo sostoyaniya kamennykh plotin s zhelezobetonnymi ekranami [Features of Analyses of the Stress-Strain State of Rockfill Dams Having Reinforced Concrete Faces]. Vestnik MGSU [Proceedings of Moscow State University of Civil Engineering]. 2006, no. 2, pp. 78—86. (In Russian)
- Sainov M.P. Vychislitel’naya programma po raschetu napryazhenno-deformirovannogo sostoyaniya gruntovykh plotin: opyt sozdaniya, metodiki i algoritmy [Computer Program for the Calculation of the Stress-strain State of Soil Dams: the Experience of Creation, Techniques and Algorithms]. International Journal for Computational Civil and Structural Engineering. 2013, vol. 9, no. 4, pp. 208—225. (In Russian)
- Park H.G., Kim Y.-S., Seo M.-W., Lim H.-D. Settlement Behavior Characteristics of CFRD in Construction Period — Case of Daegok Dam. Jour. of the KGS. September 2005, vol. 21, no. 7, pp. 91—105.
- Sainov M.P. Poluempiricheskaya formula dlya otsenki osadok odnorodnykh gruntovykh plotin [Semiempirical Formula for Assessment of Homogeneous Earthfill Dams Set]. Privolzhskiy nauchnyy zhurnal [Volga Region Scientific Journal]. 2014, no. 4 (32), pp. 108—115. (In Russian)