Experimental Analysis of Seepage Flow under Small Hydraulic Structure with Two Inclined Cutoffs

Prof. Dr. Dheyaa W. Abbood; Prof. Dr. Rafa H. AL-Suhaili; Asst. Lec.Dr. May S. Saleh

Prof. Dr. Dheyaa W. Abbood Civil Engineering Department., College of Engineering., Al-Mustansiriyha University, Baghdad, Iraq
Prof. Dr. Rafa H. AL-Suhaili Civil Engineering Department, College of Engineering, University of Baghdad, Baghdad, Iraq. A visiting professor at the City College of New York. New York, USA
Asst. Lec.Dr. May S. Saleh Civil Engineering Department., College of Engineering., Al-Mustansiriyha University, Baghdad, Iraq

Keywords: Inclined cutoff, Hydraulic structures, Geo-Studio, Uplift Pressure, Exit Gradient, Factor of Safety.

Abstract

In the present investigation, an experimental work by using physical model and numerical model by using Geo-studio software were done to test the effect of using two inclined sheet piles one located at the upstream and the other at the downstream side of the structure through a pervious soils beneath hydraulic structures. Also, it has been studied through this investigation, the effect of cutoffs inclination angle on exit gradient and uplift pressure head under hydraulic structure. Different cases were analyzed by using Geo-studio model by taking different direction of inclination of the sheet piles. Further investigation of the effects of using these inclined cutoffs with different hydraulic conductivity ratio (Kr =Kx/Ky) and various orientation of soil ellipsoid was also carried out. The results obtained from the experimental analysis were found to be comparable with that obtained from numerical model for the seepage flow, the exit gradient variation and the uplift pressure distribution. It has been concluded that when the inclination of both the upstream and the downstream cutoffs are in the adverse direction of the inclination of the soil ellipsoid, a significant reduction in uplift head is obtained, but no considerable change in the hydraulic gradient along the downstream bed.