Increase insulation effect of polyurethane board pasting on closed aqueduct surface in cold regions

Areas of northern China are mainly in the temperate monsoon climate zone and temperate continental climate zone, it is cold in winter, and the air temperature is low, which has a big influence on water diversion facilities, especially aqueduct. As for closed aqueduct water diversion projects which need to be operated in winter with non-pressure water delivery in cold regions of northern China, it is of great significance to study and research the safe operation under low temperature environment in winter.With the rapid development of the construction of water diversion projects, the original research results about aqueducts mainly lie in the structural stress of the aqueduct, then the effects of fluid-solid coupling, earthquake, wind and temperature stress, and other factors are gradually considered, seismic and reliability theory is also introduced into the design of diversion facilities. For water diversion projects in northern China, the problem of the safety of water diversion under low temperature environments in winter should also be considered. The present study in freezing disease of water diversion project and safety operation in winter is relatively less, which are mainly in the fields of monitoring analysis and numerical calculation analysis.In this paper, according to an aqueduct engineering practice with non-pressure water delivery in cold region of northern China, a scale model test of an aqueduct is undertaken in an indoor environment cabinet to study the anti-freezing and insulation effects of pasting polyurethane insulation board on the surface of the aqueduct under low temperature environment in winter. In order to study the insulation effects of polyurethane insulation board on aqueduct, the tests are mainly divided into two cases: pasting and without pasting polyurethane insulation board on the surface of the aqueduct model.By the tests, the influence of the external environment temperature and rate of flow on water flow temperature during the process of water delivery of the aqueduct in winter were studied. It is concluded from the test that pasting polyurethane insulation board on aqueduct surface has obvious effects on preventing the water temperature in the aqueduct from decreasing, reducing about 45% of the water temperature reduction. In order to ensure the insulation effects of polyurethane insulation board, polyurethane insulation board should be pasted on the surface of aqueducts closely to prevent phenomena of bulging and shedding. The aqueduct is exposed to the atmosphere and is seriously affected by the temperature, so when setting aqueduct in actual water diversion project, it should not be set too long to ensure the safe operation of these projects. Test results in the paper can provide design basis and reference for the same closed aqueduct water diversion project in cold regions of northern China.