Experimental Study of Solutions to Reduce the Effect of Soil Swelling on Concrete Lining of Conveyance Canals

Damage of canal concrete lining is one of the common problems in irrigation and drainage network projects. Results of several Studies show that swelling of unsaturated expansive soils usually led to theses damages. In recent paper, this phenomenon is studied by physical modeling. In this paper two different ways are studied to control and reduce the effect of swelling soil on canal lining. The first way is the optimization of number and location of joints on canal linig and the second is the investigation of the effect of canal wall slope on soil-lining interaction behavior. For this purpose the irrigation and drainage network of Tabriz plain canal that is under construction on expansive soil is selected as a refrence for geometric properties of canal section. The physical models are constructed as small scale (1/10) in laboratory and two techniques is used in tests: PIV method and instrumentation. By using of PIV method displacement vetors, volumetric countours and magnitude of them in bed soil are obtained and drawn. In addition the results of physical modelings show the effect of joints to control and distribute of expansive soil-canal lining interaction forces. In the other hand the strain gauges recorded data show that the relative displacement of panels and destructive bending moments of lining are decreased by considering joints on location of maximum internal forces in the canal section. Also it is inferred that the variation of canal wall slope is not an effective way to reduce the lining damages.