RESEARCH OF BUILDING MATERIALS

INFLUENCE OF COMPOUND DAM DESIGN ON ITS STRESS-STRAIN STATE

Vestnik MGSU 1/2018 Volume 13
  • Fomichev Aleksey Aleksandrovich - AO «Aquatic» Engineer, AO «Aquatic», 5, 125Zh, Varshavskoe shosse, Moscow, 117587, Russian Federation.
  • Sainov Mikhail Petrovich - Moscow State University of Civil Engineering (National Research University) (MGSU) Candidate of Technical Sciences, Associate Professor, Department of Hydraulic and Hydraulic Engineering, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation.

Pages 107-115

Subject: the dam of compound design in which the water pressure is borne mutually by a concrete gravity dam and a higher rockfill dam with reinforced concrete facing. Research objectives: 1) study the stress-strain state (SSS) of a compound dam, identify the effect of three main factors on the dam SSS. The first factor is the height of the concrete structure. The second factor is the height of the contact zone (conjugation) between the earth fill and the concrete structure. The third factor is deformability of riprap; 2) based on these studies, give recommendations for selection of the compound dam design. Materials and methods: SSS studies were conducted by numerical analysis using the finite element method (FEM). Nonlinear character of soils deformability and contacts of concrete structure with soils, foundation and reinforced concrete facing was taken into consideration. Sequence of the dam erection and loading was taken into account. Riprap’s modulus of deformation varied from 70 to 270 МPа. Results: results of the analysis showed that the concrete structure as a part of the compound dam withstands hydrostatic load almost independently, practically without transferring it to the earth fill. We have found out that the most sensitive part of the compound dam design is conjugation of the earth fill with the concrete structure. This zone is characterized by failures of the soil strength. The consequence of these failures are considerable displacements in the joint between the facing and the concrete structure as well as bending deformations of the lower part of the facing. Bending of the facing causes considerable tensile stresses. Conclusions: the results of studies permitted us to formulate the following recommendations: 1) it is not desirable to select the height of contact zone between the earth fill and the concrete structure more than 60-75 % of the concrete structure height because it leads to increase of loads borne by the concrete structure and may result in failure of strength of its contact with foundation; 2) it is not recommended to choose the height of contact between the earth fill and the concrete structure less than 30 % of the height of the latter as it results in increase of bending deformations of reinforced concrete facing; 3) for reliability of the compound dam, it is necessary to choose riprap’s modulus of deformation not lower than 200 МPа.

DOI: 10.22227/1997-0935.2018.1.107-115

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Analysis of the stress-strain state of New Exchequer combined damat static loads

Vestnik MGSU 2/2015
  • 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 .
  • Fedotov Aleksandr Aleksandrovich - Moscow State University of Civil Engineering (MGSU) student, Institute of Hydraulic and Power 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 .

Pages 141-152

In the article the authors analyze numerical modeling results of the stress-strain state of a combined dam created by construction of a higher rockfill dam with a reinforced concrete face behind the downstream face of the concrete dam. The analysis was conducted on the example of the design of 150 meter high New Exchequer dam (USA). Numerical modeling was conducted with consideration of non-linearity of soils deformation as well as non-linear behavior of the interaction “concrete - soil”, “concrete - concrete”. The analysis showed that though in a combined dam the concrete part gets additional displacements and settlements, its stress state remains favorable without appearance of tensile stresses and opening of the contact “concrete - rock”. This is explained by the fact that on the top the concrete dam is weightened by the reservoir hydrostatic pressure. The role of rockfill lateral pressure on the concrete dam stress state is small. There may be expected sliding of soil in relation to the concrete dam downstream face due to the loss of its shear strength. Besides, decompaction of the contact "soil - concrete" may occur, as earthfill will have considerable displacements in the direction from the concrete dam. Due to this fact the loads from the earthfill weight do not actually transfer to the concrete dam. The most critical zone in the combined dam is the interface of the reinforced concrete face with the concrete dam. Under the action of the hydrostatic pressure the earth-fill under the face will have considerable settlements and displacements, because soil slides in relation to the concrete dam downstream face. This results in considerable openings (10 cm) and shear displacements (50 сm) in the perimeter joint. The results of the numerical modeling are confirmed by the presence of seepage in New Exchequer dam, which led to the necessity of its repair. Large displacements do not allow using traditional sealing like copper water stops in the perimeter joint of combined dams. The sealing should be made of geo-membrane with placement of an asphalt pad under the face. Due to bending deformations in the lower part of the reinforced concrete face considerable tensile forces may occur. It is recommended to arrange a transverse joint in this part of the face.

DOI: 10.22227/1997-0935.2015.2.141-152

References
  1. Hammar E., Lennartsson D. The Yang Qu Dam: Optimization of Zones by Numerical Modelling on this New Type of Dam. Luleå University of Technology, 2014, 67 p.
  2. Reitter A.R. Design and Construction of the New Exchequer Dam — the World’s Highest Concrete Faced Rockfill Dam. World Dams Today. 1970, pp. 4—10.
  3. Garcia F.M., Maestro A.N., Dios R.L., de Cea J.C., Villarroel J., Martinez Mazariegos J.L. Spain´s New Yesa Dam. The International Journal on Hydropower & Dams. 2006, no. 13 (3), pp. 64—67.
  4. Dios R.L., Garcia F.M., Cea Azañedo J.C., Mazariegos J.L.M., Gonzalez-Elipe J.M.V. El Diseño del Recrecimiento del Embalse de Yesa. Revista de Obras Publicas/Marzo. 2007, no. 3, 475, pp. 129—148.
  5. Sherard J.L., Cooke J.B. Concrete-Face Rockfill Dam: I. Assessment. Journal of Geotechnical Engineering. 1987, vol. 113, no. 10, pp. 1096—1132.
  6. Sainov M.P. Vychislitel’naya programma po raschetu napryazhenno-deformirovannogo sostoyaniya gruntovykh plotin: opyt sozdaniya, metodiki i algoritmy [Computer Program for the Calculating 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)
  7. Rasskazov L.N., Dzhkha Dzh. Deformiruemost’ i prochnost’ grunta pri raschete vysokikh gruntovykh plotin [Deformability and Strength of Soils in High Soil Dam Calculation]. Gidrotekhnicheskoe stroitel’stvo [Hydraulic Engineering]. 1997, no. 7, pp. 31—36. (In Russian)
  8. Rasskazov L.N. Uslovie prochnosti [Strength Condition]. Trudy Instituta VODGEO. [Proceedings of the Institute VODGEО]. 1974, no. 44, pp. 53—59. (In Russian)
  9. Sainov M.P. Parametry deformiruemosti krupnooblomochnykh gruntov v tele gruntovykh plotin [Deformation Parameters of Macrofragment Soils in Soil Dams]. Stroitel’stvo: nauka i obrazovanie [Construction: Science and Education]. 2014, no. 2. Available at: http://www.nso-journal.ru/public/journals/1/issues/2014/02/2_Sainov.pdf. (In Russian)
  10. Marsal R.J. Large Scale Testing of Rockfill Materials. Journal of Soil Mech. and Foundations Division, ASCE. 1967, 93 (2), pp. 27—43.
  11. Gupta A.K. Triaxial Behaviour of Rockfill Materials. Electronic Journal of Geotechnical Engineering — Ejge.com. 2009, vol. 14, Bund J, pp. 1—18.
  12. Varadarajan A., Sharma K.G., Venkatachalam K., Gupta A.K. Testing and Modeling Two Rockfill Materials. J. Geotech. Geoenv. Engrg., ASCE. 2003, vol. 129, no. 3, pp. 206—218. DOI: http://dx.doi.org/10.1061/(ASCE)1090-0241(2003)129:3(206).
  13. Marachi N.D., Chan C.K., Seed H.B. Evaluation of Properties of Rockfill Materials. J. SMFE. 1972, 98 (1), pp. 95—114.
  14. 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.
  15. Sainov M.P. Poluempiricheskaya formula dlya otsenki osadok odnorodnykh gruntovykh plotin [Semiempirical Formula for Assessment of Homogeneous Earthfill Dams]. Privolzhskiy nauchnyy zhurnal [Volga Region Scientific Journal]. 2014, no. 4, pp. 108—115. (In Russian)
  16. Kearsey W.G. Recent Developments of Upstream Membranes for Rockfill Dams. A Thesis Submitted to the Faculty of Graduate Studies and Research in Partial Fulfilment of the Requirements for Requirements for the Degree of Master of Engineering In Geotechnique. Edmonton, Alberta, July, 1983, 132 p.
  17. ICOLD. Concrete Face Rockfill dam: Concepts for design and Construction. In-ternational Commision on Large Dams. Bulletin 141, 2010.
  18. ICOLD. Rockfill Dams with Concrete Facing-State of the Art. International Commision on Large Dams. Bulletin 70, 1989, pp. 11—53.
  19. Brown H.M., Kneitz P.R. Repair of New Exchequer Dam. Water Power and Dam Construction. 1987, no. 39 (9), pp. 25—29.
  20. McDonald J.E., Curtis N.F. Repair and Rehabilitation of Dams: Case Studies; Pre-pared for U.S. Army Corps of Engineers. Engineer Research and Development Center, 1999. 265 p.

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Study of the dam site shape effect on the behaviour of the perimeter joint of arockfill dam having a reinforced concrete face

Vestnik MGSU 9/2013
  • 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 .

Pages 101-117

The article deals with the dam site shape effect produced on values of displacements in the perimeter joint of the 100 m high rockfill dam having a reinforced concrete face. Six alternative options of the dam site were considered: 3 sites having trapezoidal shape and 3 sites having triangular shape. The options also differ in slopes of rock sides (1:2, 1:5, 1:1). Displacements in a perimeter joint were identified based on the analyses of stress-strain states of rockfill dams, completed using the method of contact finite element to model the behaviour of joints. According to the author’s findings, displacements in the perimeter joint occur in three directions: the opening, the outline deflection of the face and the longitudinal displacement of the face. In the course of the modeling process, the perimeter joint opened in all six options, because horizontal displacements of the face (in the direction along the river channel) turned to be approximately equal to its settlement. In case of narrow (triangular) sites, the maximal opening of the joint occurs on the rock sides. In case of wide sites, opening at low levels increases to a considerable extent; large openings are observed not only on dam sides, but in the river channel, as well. An opening of the perimeter joint means reduction of values of tensile forces on the face. If the perimeter joint opens, the face is free to move in other directions. Deflections may reach large values, especially if the dam site is wide and has steep rock sides. Deflections reach maximum values in the points, where the reinforced concrete face demonstrates its maximum deflection. The studies prove that the width of the dam part in the river channel has the major effect on values of displacements in the perimeter joint.

DOI: 10.22227/1997-0935.2013.9.101-117

References
  1. Stapledon D., McGregor P., Bell G., Fell R. Geotechnical Engineering of Dams. Taylor & Francis, 2005.
  2. Chartrand C., Claisse M., Beaus?jour N., Briand M.-H., Bouzaiene H., Boisjoly C., Gonzaga G., Quenneville R., Bergeron A. Toulnustouc Dam. Canadian Consulting Engineer. October-November 2006, vol. 47, no. 6, p. 51.
  3. Nichiporovich A.A., Borovoy A.A., editor. 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 and 8th International Congresses on Large Dams)]. Moscow, Energiya Publ., 1967, pp. 90—99.
  4. Concrete Face Rockfill Dam: Concepts for Design and Construction. International Commission on Large Dams. Bulletin 141, 2010.
  5. Rockfill dams with Concrete Facing-State of the Art. International Commission on Large Dams. Bulletin 70, 1989.
  6. 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.
  7. Vybornov K.A., Sainov M.P. Vliyanie raboty shvov na prostranstvennoe napryazhenno-deformirovannoe sostoyanie kamennoy plotiny s zhelezobetonnym ekranom [Effect of Behaviour of Seams on the Spatial Stress-strain State of a Rockfill Dam Having a Reinforced Concrete Face]. Vestnik MGSU [Proceedings of Moscow State University of Civil Engineering]. 2011, no. 5, pp. 12—17.
  8. Yu H., Li Sh., Liu Y., Zhang J. 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.
  9. 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.
  10. Szostak-Chrzanowski A., Massi?ra M., Deng N. Concrete Face Rockfill Dams – New Challenges for Monitoring and Analysis. Reports on Geodesy. 2009, no. 2/87, pp. 381—390.
  11. Gu Gangcheng. Trekhmernyy nelineynyy staticheskiy i dinamicheskiy analiz kamenno-nabrosnykh plotin s zhelezobetonnymi ekranami metodom konechnykh elementov [3D Non-linear Static and Dynamic Analysis of Rockfill Dams Having Reinforced Concrete Faces Using FEM]. Hohai University, Nankin, 1990.
  12. ?zkuzukiran R.S. Settlement Behavior of Concrete Face Rockfill Dams: a Case Study. Graduate School of Natural and Applied Sciences, Middle East Technical University, 2005.
  13. 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 Construction]. 2004, no. 3, pp. 2—8.
  14. Gol'din A.L., Rasskazov L.N. Proektirovanie gruntovykh plotin [Design of Earthfill Dams]. Moscow, ASV Publ., 2001, 384 p.
  15. Rasskazov L.N., Dzhkha Dzh. Deformiruemost' i prochnost' grunta pri raschete vysokikh gruntovykh plotin [Deformability and Strength of Soils for Analysis of High Earthfill Dams]. Gidrotekhnicheskoe stroitel'stvo [Hydraulic Engineering Construction]. 1997, no. 7, pp. 31—36.

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