Numerical Investigation of Foundation Drains Performance in Decreasing Uplift Force of Concrete Gravity Dams

Nourani, B; Salmasi, F; Abbaspour, A

Numerical Investigation of Foundation Drains Performance in Decreasing Uplift Force of Concrete Gravity Dams

Document Type : Research Paper

Authors

Abstract

General assumption in designing cut off walls is that the seepage be held in a limited amount.
In order to control the seepage, the foundation drains are located in parallel to cut off wall at
downstream. The main aim of foundation drains construction is to collect seepage water and decrease
uplift force. Numbers, distance, and diameters of these drains need technical judgment about
characteristics of foundation stones. The depth of drains depends on cut off wall characteristics. In
this study, the performance of drains in foundation of concrete gravity dam was investigated using
finite element method (FEM) via Seep/w software. Among influential parameters in studying the
drain effects, one might consider diameters, center to center distance, and distance of the drains from
upstream of dam. In this paper effective parameters on uplift force were analyzed and it was found
that increasing the drain diameter had lesser effect on decrease of the uplift force slightly compared
to the other parameters. In the other words, selecting the best diameters depends on executive
consideration. But decreasing the distance of drains and also their distance from upstream of dam
would play an important role in decreasing the uplift force. Focusing to the simulated range of
parameters, the drains with 15 centimeter diameter and distance of 3 meters had the optimum
performance and the best operation in decreasing uplift force. For validation, the numerical method
used in this research was compared with the other analytical methods and the proper agreement with
them was observed.

Keywords

Main Subjects

Hydraulic Structures

References

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