Abstract
In order to compute discharge over and through a rubble mound weir, a one-dimensional analysis and a laboratory experiment were carried out. Assuming a two-layer flow consisting of an open-channel flow over the weir and a turbulent seepage flow in the weir, one-dimensional momentum principle and continuity equation were formulated. In the analysis, interaction between the open channel flow and the seepage flow was taken into consideration and the shear stress at the two-layer interface was successfully evaluated. Under various conditions of weir length and height, porosity, rubble diameter and water depth, the analysis well reproduces longitudinal profiles of water surface and flow velocities over and inside the weir. The analysis also provides a solution of discharge as a function of relating hydraulic parameters such as weir's dimension, rubble's properties, and water depth at the upstream side. The solution was well correlated with the experimental data. The present study could be applied to practical use for making design of structure, discharge control, assessment of criteria of structure failure against flow.
