Trial Panels – A Useful Prerequisite for Cut off Wall Execution: Upper Gotvand Dam

Abstract—Right abutment of Gotvand Dam, the highest rock fill dam of Iran is featured by dislocated materials and anticline. Thus initial sketch of grouting curtain has been replaced by cut off wall to make it sufficiently water tight. Trial panels can illuminate probable practical obstacles for major phases. The purpose of study was to evaluate execution of support reinforced walls, brushing operation, slurry quality, and excavation efficiencies. Assessment of joint and contacts regarding accomplishment method for basement concrete has been another objective. Thus two trial phases were practiced. Then using survey panels, core sampling, and qualitative monitoring of slurry, several beneficial data were elicited. Longitudinal brushing couldn't be performed effectively. Lack of excavating completion surface provides tighter joints in between basement concrete and cut off panels. In order to prevent clay entrance in between panels and support lateral wall, guide wall has to be fabricated in same width as cutter length, otherwise differential has to be implemented as tolerance into inner panels. Observations and other data sources available were resulted in 320m long central plastic concrete wall, designed in 12 phases and 128 panels in which primary and secondary panels have 40cm overlap with each other.