抄録
The volume of expansive soil is varied when its moisture condition is changed. The results of these soil volume variation are led to cracking or uplift in light structures. One type of these vital structures is water-conveyance-lining canals. The damage of these canals impose heavy cost on irrigation and drainage network projects. In this paper two ways are studied to control and reduce the effect of swelling soil on canal lining. The first way is the optimization of number of joints on canal lining and the second is the study of location of joints on soil-lining interaction behavior. These proposed approaches have been evaluated with two methods: physical and numerical modeling. The irrigation and drainage network of Tabriz plain canal that is under construction on expansive soil is selected as a case study in this paper. The physical models are constructed as small scale (1/10) in laboratory. Also SIGMA/W 2007 software which is one of the programs in Geo-Studio software package is used for numerical modeling. The results of physical and numerical modeling show the effect of joints to control and distribute of expansive soil-canal lining interaction forces. It can be inferred from results, 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. The number and arrangement of joints should be chosen based on canal section characteristics such as geometric properties and swelling potential of bed soil. Based on obtained results for current condition, considering two series of joints are recommended in both of the canal section walls, first series near the canal floor, the intersection point of wall and floor, and second series about middle height of canal section, the concentration point of interaction forces.
