Model Experiment Of Large Roof Truss-arched Flume And Analysis By 3D-FEM

The Middle Route Project for South-to-North Water Transfer is a large typical water transfer project across drainage basins and the cities, which has an important strategetic position in the development of national economy and the construction of water conservancy. The trunk canal crosses mountains and canyons, which demands building a lot of large aqueducts. Most of them have exceeded the largest flumes of the world in span, flux and sectional dimension. The trunk canal adopts different structural styles according to the landform and geological characteristics, such as deck truss-arched structure, arch structure and single beam structure and so on. As the huge flume demands so high safety and we have no successful experiences to use for reference, we must deeply study on the design schemes of aqueducts to ensure the rationality of the design and the safety of structure.This article studied on modal pouring, assembling, loading and strain testing based on the design scheme of deck truss-arched aqueduct of CAOHE of South-to-North Water Transfer Project. At the same time analyzed the structure by universal commercial FEM software. The comparison of FEM results and experiment data testified the reliability and veracity of the two research methods and made up the defect of any single one.we simplified the model based on the symmetry of the structure, which had effectively decreased the calculative amount. The ecardinal arch design scheme of lower truss-arch reinforced the vertical stiffness and the stability of the structure, but the scheme made the structure to be sensitive to the temperature change and rigid body transition of the end abutment. According to the characteristics of ecardinal arch and its merits and faults, an effective solution that adopting temporary gemel can decrease the influence was put forward. Comparing the stress results of ascending temperature with descending temperature, we found that ascending temperature is benefit to the whole structure, so we suggested jointing closure when the temperature is lower.In the analysis, we simply simulated the contact way between launder and support, which decreased the calculative amount ulteriorly and accelerated the analysis. Comparing with the normal contact calculative results, we found that the simple results will be right when the supports have no vertical tension stress. In addition, considering the effect of construction procedure to the stress of truss-arch, we simulated the assemble order by breath and death calculation. After the analysis, we suggested that the launder should be hoisted by the sequence of middle before end. At last, we brought forward the treating and improving method to make up for the deficiency of the structure.The study indicated that the FEM method which can decrease research expenditure and shorten research period has already been sophisticated, and the analysis can be right as long as the model, loading and boundary condition is all correct. Deck truss-arched aqueduct is fit to the demand of big span, we must make use of advanced construction technology to ensure the safety of structure and decreasing the influence of temperature change and transition of end abutment. We also can adopt segment pouring method at the arch crown and apply prestress. The analysis of FEM has obtained stress regularities of distribution and the influence of all base load. This article has referenced value to the design and construction of the same kind of aqueduct.