Influence of filling rate on stress state and deformation behavior of Longyang Reservoir embankment dam: A model analysis

The length of the Longyang Reservoir embankment dam is 1.63 km， and its foundation is covered by thick saturated loess， promoting the possibility of uneven settlement. In order to determine the reasonable dam construction rate of Longyang storage tank on saturated deep cover layer， the variation law of soil rock dam foundation consolidation degree with time and loading rate in rectangular and trapezoidal average consolidation degree models was studied. The settlement models are solved by layer-wise summation and finite element methods. The total settlement and corresponding stress distributions， and the variation of settlement under different filling rates are examined. The results indicate that the settlement of embankment dam foundation is basically stable after the 1100th day of construction， and consolidation degree exceeds 90% after 3 years of construction. The final settlement of embankment dam foundation is calculated through recommended calculation method of Code for Design of Building Foundation and the layer-wise summation method， and it is found that calculation results are basically the same， ranging between 1.56-1.58 m. The calculation results using finite element method show that settlement during completion period decreases with the increase of filling rates， and the total settlement range during completion period is between 1.63-2.12 m. When the filling rate exceeds 0.5 m/d， the minor principal stress value of dam surface exceeds cohesion of embankment dam filling soil， indicating that tension cracks may occur in the dam body during the construction process. Thus recommended that the filling rates is less than 0.5 m/d. These results can provide reference for the settlement control of water conservancy facilities on thick saturated loess foundations.