Abstract
Toe formation is a phenomenon resulting from unconnected cracks between blastholes,which occurred during blasting excavation of the abutment slot at Baihetan hydropower station. Analysis of crack development has tended not to focus on the high in-situ stress environment at the slope corner. Therefore, this study aimed to explore the toe formation process through theoretical analysis and numerical simulation. Firstly, a three-blasthole model was established to analyze the effects of blasting load and in-situ stress on crack extension. Then, a finite-element model of the abutment slot was built to simulate crack propagationunder different in-situ stress environment. Finally, optimization measures for avoiding toe were proposed. The results demonstrate that cracks grow preferentially in the direction of the maximum tangential tensile stress and are influenced by the blasting load and in-situ stress. On the lateral side of the abutment slot, the crack initiation and extension occur far from the centerline due to the deviation of the maximum tangential tensile stress. The deviation increased as the in-situ stress. Consequently, cracks between blastholes not being able to connect with each other results in toe formation. Increment of the linear density of the charge and optimization of the excavated profile are both effective in reducing the impact of the stress concentration caused by in-situ stress and preventing toe formation.
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Acknowledgments
This work is supported by Chinese National Natural Science Foundation (No.51779193 and No.51979205) and Open Innovation Funds for the Changjiang Institute of Survey, Planning, Design and Research (CX2020K08). The authors wish to express their thanks to the supporter.
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Deng, K., Chen, M., Yan, P. et al. Analysis of Toe Formation in Stress-Concentration Zones on High Rock Slopes. KSCE J Civ Eng 26, 966–976 (2022). https://doi.org/10.1007/s12205-021-0705-6
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DOI: https://doi.org/10.1007/s12205-021-0705-6