Numerical Study of the Long-Term Performance of an Underground Powerhouse Subjected to Varying Initial Stress States, Cyclic Water Heads, and Temperature Variations

Abstract

Many large underground structures may be subjected to varying initial stress states, cyclic water heads, and long-term temperature variations. When the maintenance and extension of the service life of such structures are accounted for, their long-term performance under varying initial stress states, cyclic water heads, and temperature variations becomes very important. The authors were involved with the evaluation of the long-term performance of an underground powerhouse in central Japan constructed for a pumped-storage scheme. The evaluations involved both numerical studies on the long-term effects of varying initial stress states, cyclic water heads, and temperature variations on the performance of the powerhouse considering the degradation of support systems and creep phenomenon and the monitoring of ground deformations, temperatures, and vibrations induced by turbines. The outcome of these studies are presented in this article.