Abstract:
In earth dams with a simple geometry, especially when the valley width is large, various analyses are performed in two-dimensional plain strain condition. In contrast, when the valley width is small or dam foundation is not uniform, the dam structure would be three dimensional and requires 3D analysis. Furthermore, valley slope of and dam sides may influence the dam behavior. The main objective of this study is to investigate valley slope on the behavior of earth dams at end of construction, first impounding, steady seepage stages, and under dynamic loading. Therefore, three similar earth dam with the different valley slopes (30 , 45 and 60 ) were analyzed. Results of analysis show that the valley slope has no significant impact on arching phenomenon and maximum pore water pressure and minimum settlement at the end of construction are associated with the dam with valley slope of 30. Results of the study indicate that the pore water pressure induced by dynamic loading is independent from valley slope and response acceleration of dam crest increases by an increase in the slope of valley.
Machine summary:
In this regard, three similar earth dam are constructed on valley with different slopes, and analyzed in construction and dewatering level, and steady leakage under earthquake loading; the effect of valley slope on behavior of this dam, such as arcing phenomena, deformation and pore water pressure were studied.
arcing ratio changes in section 2-2 at the end of construction for balance a) zero, b) 17 and c) 34 meters Pore water pressure During performance of earth dams and simultaneous with increase of dam height, additional pore water pressure is created due to the weight of upper layers inside the core material.
These figures indicate increase of valley slope decreases pore water pressure created in all three sections, especially in middle part of dam height.
pore water pressure changes due to end of construction in section 1-1 for valley with 30º , 45º , 60º slopes Dynamic analysis Arcing Regarding the importance of vertical stress and arcing phenomena, this part studies arcing phenomena under applying dynamic loads.
Maximum pore water pressure of static analysis is 365 Kpa in section 2-2 in dam with valley slope of 30 degree and in height of 12 meters of dam foundation.
However, maximum pore water pressure in dynamic analysis occurs for dam with valley slope of 45 degree in section 1-1 and height of 5 meters from dam foundation.
pore water pressure changes due to first dewatering in section 1-1 for valley with slopes: a) 30º , b) 45º , c) 60º (View the image of this page) Figure 12.