Narrow Canyon Effect on the Behavior of Earth Dams at the End of Construction (Case Study: Vanyar Dam)

Abstract

Earth dams are geotechnical structures constructed on various shapes of a valley. The Vanyar Dam is a rock-fill dam located on a narrow valley. Concerning the geometry of the canyon, three-dimensional modeling was utilized to analyze this dam. According to the numerical analysis, the maximum settlement is 88.14 cm, which corresponds to 48 m above the bedrock in cross-section C, that is, a little less than 1% of the dam height. Besides, the total vertical stresses recorded by the pressure cells are about 28% less than those obtained from the numerical analysis. It is assumed that the difference is caused by local arching due to lower compaction and consequently a low stiffness area around the pressure cells. In terms of pore water pressure, there is good agreement between the pore water pressure obtained from the numerical analysis and the piezometers, such that the results are restricted to less than 1%. In general, the difference between the numerical analysis results and those recorded by the instruments is acceptable. Furthermore, the dam shows a suitable level of performance at the end of construction.