Dynamic in-plane transversal normal stresses in the concrete face of CFRD

Neftalí Sarmiento-Solano1, Miguel P. Romo1
1Institute of Engineering, National University of Mexico, Mexico City, Mexico

Tóm tắt

Severe earthquakes can induce damages to Concrete Face Rockfill Dams (CFRDs) such as concrete cracking and joint’s water stops distressing where high in-plane transversal normal stresses develop. Although these damages rarely jeopardize the dam safety, they cause large water reservoir leakages that hinder the dam functioning. This issue can be addressed using well know numerical methods; however, given the wide range of parameters involved, it would seem appropriate to develop a simple yet reliable procedure to get a close understanding how their interaction affects the CFRD’s overall behavior. Accordingly, once the physics of the problem is better understood one can proceed to perform a detailed design of the various components of the dam. To this end an easy-to-use procedure that accounts for the dam height effects, valley narrowness, valley slopes, width of concrete slabs and seismic excitation characteristics was developed. The procedure is the dynamic complement of a method recently developed to evaluate in-plane transversal normal stresses in the concrete face of CFRD’s due to dam reservoir filling [1]. Using these two procedures in a sequential manner, it is possible to define the concrete slab in-plane normal stresses induced by the reservoir filling and the action of orthogonal horizontal seismic excitations acting at the same time upstream-downstream and cross river. Both procedures were developed from a data base generated using nonlinear static and dynamic three-dimensional numerical analyses on the same group of CFRD’s. Then, the results were interpreted with the Buckingham Pi theorem and various relationships were developed. In the above reference, the method to evaluate the concrete face in-plane transversal normal stresses caused by the first reservoir filling was reported. In this paper, the seismic procedure is first developed and then through an example the whole method (dam construction, reservoir filling plus seismic loading) of analysis is assessed.

Tài liệu tham khảo

Zhang J, Yang Z, Gao X, Tong Z. Lessons from Damages to High Embankment Dams in the May 12, 2008 Wenchuan Earthquake. Soil Dynamics and Earthquake Engineering, Geotechnical Special Publication, ASCE, 2010; 201: 1–31

Sarmiento N, Romo M P. Efecto de la dirección de la excitación en la respuesta sísmica de la cara de concreto de presas de enrocamiento. IMTA-TC, 2013, IV(2): 91–111 (in Spanish)

Romo M P. Cuestiones sísmicas de nuevos tipos de presas. Memorias del coloquio conmemorativo: La Ingeniería Geotécnica a 20 años de “El sismo”. Ciudad de México, 2005, p. 159–163 (in Spanish)

Wieland M. Concrete Face Rockfill Dams in Highly Seismic Regions. In: The proceedings of the 1st International Symposium on Rockfill Dams, Chengdu, China, October, 2009

Taylor E S. Dimensional analysis for engineers. Clarendon Press, Oxford, 1974, pp 162

Itasca Consulting Group. FLAC3D: Fast Lagrangian Analysis of Continua in 3 Dimensions. Inc., Minneapolis, Minnesota, 2005

Cundall P A, Hart R D. Numerical modeling of discontinua. Engr. Comp, 1992, 9(2): 101–113

Méndez B C. Investigación experimental de la fricción dinámica en una interfaz madera sobre madera. Tesis de maestría, Universidad Nacional Autónoma de México, 2004 (in Spanish)

Alberro J, Macedo G and Gonzalez F. Deformabilidad in situ de los materiales constitutivos de varias presas de tierra y enrocamiento. Informe para la Comisión Federal de Electricidad, Instituto de Ingeniería, Universidad Nacional Autónoma de México. May 1998 (in spanish)

Romo M P. Performance of El Infiernillo and La Villita dams including the earthquake of March 14, 1979. Ediciones del Sector Eléctrico, 1980, No 15, CFE, Chapters 6 and 7

Romo M P, Villarraga R. Theoretical model for the seismic behavior of dams: El Infiernillo. Series del Instituto de Ingeniería, UNAM, 1989, No 518 (in Spanish)

Romo M P, Magaña R. Evaluation of the seismic response and safety of El Infiernillo and La Villita dams. Internal report, Instituto de Ingeniería, UNAM, 1992 (in Spanish)

Romo M P. Model development from measured seismic behavior of earth-rockfill dams. Series Investigación y Desarrollo, Instituto de Ingeniería, UNAM, 2002, SID/630

Romo MP, Sarmiento N, Martínez S, Merlos J, García S R, Magaña R, Hernández S. Análisis Sísmico de la Cortina Propuesta por CFE para el Proyecto Hidroeléctrico El Cajón y Diseños Geotécnicos Alternos. Informe Técnico del Instituto de Ingeniería, UNAM, elaborado para la Comisión Federal de Electricidad, noviembre, 2002 (in Spanish)

Romo M P, Sarmiento N and Martínez S. Análisis sísmico de la cortina (enrocamiento con cara de concreto) de la presa La Parota, Informe Técnico del Instituto de Ingeniería, UNAM, elaborado para la Comisión Federal de Electricidad, 2004 (in Spanish)

Romo M P, Botero E, Méndez B, Hernández S, Sarmiento N. Análisis sísmico de la cortina y el vertedor del proyecto Hidroeléctrico La Yesca. Informe Técnico del Instituto de Ingeniería, UNAM, elaborado para la Comisión Federal de Electricidad, julio, 2006 (in Spanish)

Romo M P. Soil-structure interaction in a random seismic environment. PhD Thesis, University of California, Berkeley, 1976

Romo M P, Chen J, Lysmer J, Seed H B. PLUSH. A Computer Program for Probabilistic Finite Element Analysis of Seismic Soil-Structure Interaction. Earthquake Engineering Research Center, Report EERC-77/01, University of California, Berkeley, California, 1980

Sarmiento N. Respuesta sísmica tridimensional de presas de enrocamiento con cara de concreto. Tesis doctoral, Universidad Nacional Autónoma de México, 2011 (in Spanish)