Effect of clay-concrete lining on canal seepage towards the drainage region – an analysis using Finite-Element method

For proper design of a drainage system that utilizes lined canals, knowledge of the seepage into a soil substrate/drainage region is necessary so that the drainage blanket and /or filter type and thickness, and the size of collector pipes can all be designed. The work presented in this paper is based on the problem of steady-state seepage from a hypothetical irrigation canal into the substrate/drainage region towards asymmetrical trapezoidal concrete-lined canal. The problem is solved using a finite element based software program to determine the flow volume into the drainage region. Typical values of soil permeability coefficients of single and two-layer subsoil from literature are used along with experimental results of a laboratory study done for the design seepage coefficient of clay-cement concrete as lining material. The water flow effect of canal seepage discharge analyzed shows that the effectiveness of canal lining in reducing seepage is less when drainage distance is large. This study may contribute towards a better understanding on design of hydraulic conductivity under hydraulic structures. It will systematically enumerate the many, often straightforward factors that determine coefficient of permeability for compliance purposes. This could also involve a re-estimation of the values of the permeability coefficient and the factors on which the coefficient depends