The Construction Method’s Comprehensive Evaluation About U-type Prestressed Anchor Cables In The Gate Piers Of High Arch Dam

Prestressed gate pier is the major components of the building releasing flood water,The stress state in the anchorage zone of gate pier is more complex than the generalanchorage element end, because needing to consider the spatial effect and group effectof anchor cables, so, it is a technical problem which is need to be solved properly.Analysing the working state of prestressed gate pier and the function the primary anchorcables and secondary anchor cables, arranging anchor cables and reinforcement by areasonable way, are very important and significative to save investment, improve thestructure performance and guarantee the safety of the structure operating.The application of U-type prestressed anchor cables creates a new form ofprestressed anchorage for hydropower projects of china. In terms of constructiontechnology about U-type prestressed anchor cables, there are three main types: in ErtanHydropower Station, anchor cables in gate piers in the middle of high arch dam which isused to release flood water are integral-crossed and single-tensioned; in GoupitanHydropower Station, anchor cables are single-crossed (each steel strand cable throughan independent duct) and integral-tensioned; in Xiluodu Hydropower Station, anchorcables are integral-crossed and integral-tensioned. The three construction technologieshave advantages and disadvantages, as for which is optimal, there is not theoreticalproof.In this paper, taking construction technology of the U-type prestressed anchorcables in the gate piers of high arch dam(the construction method of U-type prestressedanchor cables in the gate piers of high arch dam for short)from the Ertan HydropowerProject, Goupitan Hydropower Project and Xiluodu Hydropower Project as the researchcontent, comprehensively evaluating typically several construction methods of U-typeprestressed anchor cables in the gate piers of high arch dam. The main work and theachievements completed are as follows:①Respectively, introducing and analysing project overview of the Ertanhydropower station, Goupitan Hydropower station, and Xiluodu hydropower station andtheir construction characteristics of U-type prestressed anchor cables’ constructionmethods in detail, which is taken as engineering background of scheme comparison.②As for the construction method of U-type prestressed anchor cables in the gatepiers of high arch dam, analysing and assessing their various influence factors during the process of construction, and taking these factors as comprehensively comparativeand evaluative indexes.③Establishing fuzzy AHP comprehensive evaluation model of the constructionmethod about U-type prestressed anchor cables in the gate piers of high arch dam aboutconstruction technology by fuzzy AHP comprehensive evaluation method, and studyingthe steps which use the model to comprehensively evaluate the construction method ofU-type prestressed anchor cables in the gate piers of high arch dam detailedly. First ofall, establishing comprehensively evaluative indicator system of the constructionmethod about U-type prestressed anchor cables in the gate piers of high arch dam andcalculating the weights of evaluation indexes by fuzzy analytical hierarchy process,what’s more, using fuzzy comprehensive evaluation method to estimate the influencedegree which evaluative indexes have on the construction method of U-type prestressedanchor cables in the gate piers of high arch dam, at last, according to estimated results,determining the level of various factors.④Extracting evaluative indexes of Ertan hydropower project, GoupitanHydropower project, and Xiluodu hydropower project about the construction method ofU-type prestressed anchor cables in the gate piers of high arch dam, applying fuzzyAHP comprehensive evaluation model to construction technology of the U-typeprestressed anchor cables in the gate piers of the three major hydropower projects: Firstof all, in the longitudinal direction, using fuzzy comprehensive evaluation method todetermine the importance of each factor in the single Hydropower project about theconstruction method of U-type prestressed anchor cables in the gate piers of high archdam, and then comprehensively evaluating the construction method of U-typeprestressed anchor cables in the gate piers of high arch dam about the three hydropowerprojects in the horizontal direction. At last, through analysing the results evaluated,determining the best construction technology, and the evaluation results are consistentwith the practice engineering.