Background Dams are substantial structures that accumulate an immense volume of water, and their collapses inflict irreversible loss of life during earthquakes. They are referred to as a category of structures that interact with fluids. Thus, the structural assessments should represent more precisely the interaction between fluid–structure and its hydrodynamic pressures to ascertain the actual field behavior. Purpose and Methodology/Approach The influence of hydrodynamic pressure on the dam body may be computed using many mathematical and analytical modelling techniques. The purpose of this research is to explore the dynamic response of concrete gravity dam (CGD) by incorporating the hydrodynamic effect by using the Westergaard water modelling technique. The Bhakra-Nangal CGD situated on the Sutlej River in Bilaspur (Himachal Pradesh), is chosen as a case study for this purpose. Subsequently, the finite element (FE) models of the dam are developed, while incorporating the interaction between the different components of the integrated structure (dam-reservoir-foundation) by using ANSYS software. Linear transient analysis is conducted using the 1991 Uttarkashi earthquake ground motion data to ascertain the structural behavior of the dam and the Rayleigh damping is considered as 5% during the analysis. Results The results prove that the soil structure interaction (SSI) has the substantial effect on the dynamic response of the integrated structure. At the completion of the findings, the study found that there is substantial variation (around 49.3%) in the crest displacement of the dam when compared to both with or without SSI. Further, the stability of the structure is analysed for various critical parameters like reservoir depth (RD), flexibility ratio (Ef/Ed) and it can be deduced from the results that there is a significant rise in crest displacement about 59.5% and 297.4% when the soil base flexibility ratio (Ef/Ed) is substantially decreased to 0.5 and 0.25 respectively. Moreover, it is found that the magnitude of the stress value has increased by 37.21% and 51.1% corresponding to flexibility ratio of 0.5 and 0.25 respectively. Conclusion The research assists in the identification of critical locations in the coupled structure that are susceptible to the development of tension fractures. The neck region, which is situated at 146.26 m from the dam's base and is essentially the transition point between the base width and the crest portion, is more susceptible to the development of tension cracks, as the stress concentration in the neck region is higher than the material's tensile strength, according to the analysis results.

Seismic Response Assessment of Concrete Gravity Dam with Dam-Foundation-Reservoir Interaction by Adopting Finite Element Technique

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发表日期：

2025年5月27日

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Abhishek Sharma,
Sahil Thakur,
K. Nallasivam

摘要

Background

Dams are substantial structures that accumulate an immense volume of water, and their collapses inflict irreversible loss of life during earthquakes. They are referred to as a category of structures that interact with fluids. Thus, the structural assessments should represent more precisely the interaction between fluid–structure and its hydrodynamic pressures to ascertain the actual field behavior.

Purpose and Methodology/Approach

The influence of hydrodynamic pressure on the dam body may be computed using many mathematical and analytical modelling techniques. The purpose of this research is to explore the dynamic response of concrete gravity dam (CGD) by incorporating the hydrodynamic effect by using the Westergaard water modelling technique. The Bhakra-Nangal CGD situated on the Sutlej River in Bilaspur (Himachal Pradesh), is chosen as a case study for this purpose. Subsequently, the finite element (FE) models of the dam are developed, while incorporating the interaction between the different components of the integrated structure (dam-reservoir-foundation) by using ANSYS software. Linear transient analysis is conducted using the 1991 Uttarkashi earthquake ground motion data to ascertain the structural behavior of the dam and the Rayleigh damping is considered as 5% during the analysis.

Results

The results prove that the soil structure interaction (SSI) has the substantial effect on the dynamic response of the integrated structure. At the completion of the findings, the study found that there is substantial variation (around 49.3%) in the crest displacement of the dam when compared to both with or without SSI. Further, the stability of the structure is analysed for various critical parameters like reservoir depth (RD), flexibility ratio (E_f/E_d) and it can be deduced from the results that there is a significant rise in crest displacement about 59.5% and 297.4% when the soil base flexibility ratio (E_f/E_d) is substantially decreased to 0.5 and 0.25 respectively. Moreover, it is found that the magnitude of the stress value has increased by 37.21% and 51.1% corresponding to flexibility ratio of 0.5 and 0.25 respectively.

Conclusion

The research assists in the identification of critical locations in the coupled structure that are susceptible to the development of tension fractures. The neck region, which is situated at 146.26 m from the dam's base and is essentially the transition point between the base width and the crest portion, is more susceptible to the development of tension cracks, as the stress concentration in the neck region is higher than the material's tensile strength, according to the analysis results.