Application of numerical simulation in determining the position and dimensions of weep hole of concrete channel under different groundwater levels

Abstract

One of the most important problems of irrigation networks is damage to the concrete's canal, which resulted from uplift forces in many cases. The uplift force is created due to the lack of control of the hydrostatic pressure of groundwater on the side wall and the bottom of the canal. The aim of this study is to investigate the position and dimensions of weep hole in the floor and side walls of the concrete channel and its effect on the of reverse leakage flow, uplift forces and hydraulic gradient in different levels of groundwater. For this purpose, a concrete channel with hypothetical geometry over the permeable foundation was simulated by Seep/W software. The variables of the study included dimensions and different positions of weep hole under three different levels of groundwater.The results showed that in all dimensions of weep hole, increasing groundwater depth increase the linear reverse leakage flow rate into the concrete channel and the exist hydraulic gradient. Also, in all weep holes, increasing the diameter reduces the uplift force. If two weep holes are used, the reverse leakage flow into the canal and the uplift forces are respectively more and less than a weep hole. In other words, the placement of two weep holes at positions N=6 and 7 showed a good performance in terms of uplift forces and inverse leakage flow. If two weep holes were placed in positions N=2 and 3, it had the best performance in terms of the exist hydraulic gradient.

Keywords

• exist hydraulic gradient
• reverse seepage discharge
• uplift force
• seep/w
• weep hole