As a type of pyroclastic rock, the breccia lava in the dam foundation of the Baihetan Hydropower Project is characterized by relatively low density, high natural moisture content and porosity, and lower ultrasonic velocity. When it is used as a bearing rock, its mechanical behavior will be critical for the safety and stability of the world’s second largest hydropower station. Therefore, uniaxial and triaxial compression tests were performed to study the mechanical behavior of the breccia lava and scanning electron microscope (SEM) tests were carried out to reveal the microscopic failure modes of this rock. The experimental results indicated that all critical stresses, including the crack initiation stress (σci), crack damage stress (σcd), and peak stress (σp), exhibit strong dependence on the confining pressure. Experiential functions were used to describe the evolution of the elastic modulus and Poisson’s ratio with confining pressure. Grain crushing and the growth and frictional sliding of microcracks were determined to cause the failure of the specimens. Based on the experimental results, a coupled elastoplastic damage model was proposed within a thermodynamic framework. In this model, two separate loading functions were employed to describe the damage and plasticity behavior of the breccia lava. A computational integration algorithm with high numerical accuracy and efficiency was developed to deal with the material under three different loading conditions: plasticity, damage, and coupled elastoplastic damage. The model was validated through comparison with the experimental data, and the good agreement between the two datasets confirms that the model can provide a good representation of mechanical behavior, particularly the post-peak behavior of the breccia lava.
Breccia lava Baihetan Hydropower Project Mechanical behavior Elastoplastic damage model
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The research described in this paper was financially supported by the National Natural Science Foundation of China (grant nos. 11572110, 51479049, 51679069, and 51609070) and the Fundamental Research Funds for the Central Universities (grant no. 2016B05314), and the Qinglan Project is gratefully acknowledged.
Bieniawski ZT (1967) Mechanism of brittle rock fracture. Part I. Theory of the fracture process. Int J Rock Mech Min Sci 4:395–406CrossRefGoogle Scholar
Brace WF (1964) Brittle fracture of rocks. In: Judd WR (ed) State of stress in the Earth's crust, proceeding of the international conference. American Elsevier Publishing Company, Santa MonicaGoogle Scholar
Fairhurst CE, Hudson JA (1999) Draft ISRM suggested method for the complete stress-strain curve for intact rock in uniaxial compression. Int J Rock Mech Min Sci 36:281–289Google Scholar
Grindrod PM, Heap MJ, Fortes AD, Meredith PG, Wood IG, Trippetta F, Sammonds PR (2010) Experimental investigation of the mechanical properties of synthetic magnesium sulfate hydrates: implications for the strength of hydrated deposits on Mars. J Geophys Res 115:E06012. https://doi.org/10.1029/2009je003552
Hansen N, Schreyer H (1994) A thermodynamically consistent framework for theories of elastoplasticity coupled with damage. Int J Solids Struct 31:359–389CrossRefGoogle Scholar
Shi A, Tang M, Zhou Q (2008) Research of deformation characteristics of columnar jointed basalt at Baihetan hydropower station on Jinsha river. Chin J Rock Mech Eng 27:2079–2086 [in Chinese]Google Scholar
Simo JC, Hughes TJ (1998) Computational inelasticity, volume 7 of interdisciplinary applied mathematics. Springer-Verlag, New YorkGoogle Scholar
Simo JC, Ortiz M (1985) A unified approach to finite deformation Elastoplastic analysis based on the use of Hyperelastic constitutive-equations. Comput Methods Appl Mech Eng 49:221–245. https://doi.org/10.1016/0045-7825(85)90061-1
Sirdesai NN, Mahanta B, Ranjith PG, Singh TN (2017a) Effects of thermal treatment on physico-morphological properties of Indian fine-grained sandstone. Bull Eng Geol Environ. https://doi.org/10.1007/s10064-017-1149-6
Song Z, Liu Y, Yang Q (2016) Experimental and numerical investigation on the stability of a high arch dam with typical problems of nonsymmetry: Baihetan Dam, China. Bull Eng Geol Environ 75:1555–1570CrossRefGoogle Scholar
Tapponnier P, Brace W (1976) Development of stress-induced microcracks in westerly granite. Int J Rock Mech Min Sci 13:103–112CrossRefGoogle Scholar
Vermeer PA, De Borst R (1984) Non-associated plasticity for soils, concrete and rock. Heron 29:3–64Google Scholar
Wang S, Xu W, Jia C, Wang W (2017) Mechanical behavior of fine-grained sandstone in triaxial compression and elastoplastic modeling by return mapping algorithms. Bull Eng Geol Environ:1–11 https://doi.org/10.1007/s10064-017-1094-4
Xiao Y-X, Feng X-T, Feng G-L, Liu H-J, Jiang Q, Qiu S-L (2016) Mechanism of evolution of stress–structure controlled collapse of surrounding rock in caverns: a case study from the Baihetan hydropower station in China. Tunn Undergr Space Technol 51:56–67CrossRefGoogle Scholar
Zhang W, J-p C, Liu C, Huang R, Li M, Zhang Y (2012) Determination of geometrical and structural representative volume elements at the Baihetan Dam site. Rock Mech Rock Eng 45:409–419CrossRefGoogle Scholar