Analysis Of Deformation Character Longyangxia Dam

Longyangxia dam has undergone the tribulation of 50 years meet flood in 1989and 2581.08 m high water level in 1999 since it was operated from Oct 1986. Therewere some "doubtful points" during this period, especially the cracks (the maximumdepth was 6 m) on downstream face which were found in the work of safetyauthentication in 1999. What caused the doubtful point of the deformation and thecracks? Can the crack maintain stabilization? What are the effects on the dam entireintensity by cracks? Replying these problems correctly is the research aim of thispaper. In the method of research, firstly, general qualitative and quantitative analysisis made on horizontal displacements of deformation doubtful points. Spatio-temporalanalytical method is taken in qualitative analysis. In quantitative analysis we establishpoint and space numerical model (statistical model, certain model and mixed model)and use these models to separate the contributions in order to make analysis andevaluation on horizontal displacement of the dam (including explanation on thedeformation doubtful points of dam). Secondly, Establish the 3D finite element modelaccording to the crack distribution and attributes of Longyangxia dam. Analyze theload case that cracks happened according to the supervised data. Choose thecalculating parameters by design and back analyzing parameters. Analyze thedisplacements in typical load case through finite element method and compare thecalculated value with proto type value in order to proof the reasonable of finiteelement model and calculating parameters. Make analysis on temperature field intypical load case using the finite element model and calculating parameters. Study thestress of downstream face with and without considering the horizontal slot. All thesethings are used to analyze the causing of cracks. At the same time, calculate the stressintensity factor of the typical cracks in typical load case by extrapolation in order toanalyze the stability of cracks on downstream face. Finally, draw the followingconclusions on character deformation of dam: â‘ The horizontal displacements of adam change periodically with years and is mainly affected by the temperature. Thewater level of the reservoir also affects it extremely, especially to the foundation of adam. Time-related contributions are stable or approach to stabilization. So thehorizontal displacements of a dam are normal as a whole.â‘¡By using the analysis of3D finite element method, it is thought that the cracks on the downstream ofLongyangxia dam are caused by the decrease of the temperature, also by the high 4water level. â‘¢ By the analysis to the stability of the cracks, we know that most ofthe cracks are stable and very few vertical cracks are unstable. But they will becomestable when their depths expand to 3~4 m or fall across the vertical cracks. The effectsof the cracks to the whole dam are comparatively small.â‘£The deforms of thehorizontal displacements are mainly caused by the observation or the special loads.The process of deformation caused by special loads is considered as a normaladjustment process.