Experimental and Numerical Investigations on the Mechanical Behavior of Basalt in the Dam Foundation of the Baihetan Hydropower Station

The mechanical behavior of basalt is critical to the stability and safety of large structures erected on basalt. In this paper, a series of tests (hydrostatic compression test, triaxial compression tests, and triaxial cyclic loading test) are conducted on basalt specimens from the Baihetan hydropower station in southwest China. The test results show that the crack closure (sigma(cc)), crack initiation (sigma(ci)), and crack damage (sigma(cd)) stresses are approximately 39%-43%, 54%-68%, and 74%-96% of the peak strength (sigma(p)), respectively. Based on the experimental results, a coupled elastoplastic damage model is proposed for basalt within a thermodynamic framework. In this model, elastic stiffness is affected by induced damage. Linear yield function and nonassociated flow rule are used to control inelastic dilatancy. Model parameters are determined from the triaxial compression tests and triaxial loading tests performed in this study. Comparison between numerical results and test results shows that the proposed model can accurately simulate the mechanical behavior of basalt under triaxial compression conditions.

Automated summary

This study conducted mechanical behavior tests on basalt specimens from the Baihetan hydropower station and proposed a coupled elastoplastic damage model. The test results showed that the crack closure, crack initiation, and crack damage stresses were approximately a certain percentage of the peak strength. The numerical simulation results were in good agreement with the test results, indicating that the proposed model accurately simulates the mechanical behavior of basalt under triaxial compression conditions.