Seite - 1290 - in Book of Full Papers - Symposium Hydro Engineering

COMMISSION INTERNATIONALE DES GRANDS BARRAGES ------- VINGT-SIXIÈME CONGRÈS DES GRANDS BARRAGES Autriche, juillet 2018 ------- AN INTELLIGENT COOLING CONTROL METHOD AND SYSTEM FOR XILUODU ARCH DAM CONSTRUCTION Peng Lin, Zeyu Ning Department of Hydraulic Engineering, TSINGHUA UNIVERSITY, BEIJING 100084 CHINA 1. INTRODUCTION In hydraulic engineering, heat of hydration develops in fresh concrete, associated with the exothermic chemical reactions of the cement [1]. Due to the poor conductivity of concrete, high temperature gradients may occur between the interior and the surface of the structural elements or between parts of an element with sequential concreting phases [2]. The temperature gradients may lead to tensile stresses and excessive tensile strength will result in the young concrete to crack [3]. Artificial water pipe cooling is an important method used to reduce the interior temperature rise of mass concrete, which can keep the concrete temperature stay near the designed value and to make the construction procedure and property controllable. The first time that water cooling used in hydraulic engineering dated back to the 1930s, when U.S. Bureau of Reclamation tested it in Owyhee concrete arch dam and got a satisfactory result in 1931. Two years later, in the construction of Hoover dam, pre-planted cooling pipes were applied in total concrete pouring blocks and the cooling result was good. Since then, cooling pipes were widely used in concrete dam for its flexibility, reliability and versatility. The method of pre-planted cooling pipes was used in the first concrete arch dam, Xianghongdian dam, for the first time in China and the result of cracking prevention was good. After that, the method was applied in many large hydraulic engineering projects like the Three Gorges Dam, Ertan dam, Xiluodu dam etc. Much engineering practice proved that the method of water cooling has been an 1290