Destructive Testing of Horseshoe-shaped Irrigation Tunnel with a Void behind Concrete Lining

Abstract

Many irrigation tunnels were constructed using the mountain tunnel method. Because of the immaturity of this construction technology in the past, some tunnels have a continuous void behind a concrete lining. In this study, destructive testing of horseshoe-shaped irrigation tunnels was carried out to identify the effect of that void. The specimen used consisted of a mortar lining was surrounded by ground. The neighboring ground was made with low-strength mortar. A vertical deformation was executed to specimens with different void ranges.

In cases where there was no void, or the range of the void was 30 degree, the lining was deformed in the vertical direction. Whereas, in cases where the void range was 60 or 90 degree, the neighboring ground pushed the lining into the tunnel with the progress of the deformation. Finally, a longitudinal crack occurred in the arch of the lining, and the inner section was expanded in the vertical direction and reduced in the horizontal direction.