Research On Analysis Of Dam Observed Data And Safety Evaluation For Xi'an Heihe Earth Core Rockfill Dam

The safety evaluation of high earth core rockfill dam through deformation and seepage measurement and analysis is one of most important problems in nowdays soil mechanics.As the influences of construction technics, construction method and construction quality during construction period and manage method and manage environment during operation period, soil real parameters of the dam are different from the original parameters. If the original parameters are used to evaluate the safety of the dam, it certainly will induce insurmountable misplays. So it is very significant to back- analyze soils real parameters and get the actual running state of dam using in-situ observed data, then to evaluate the dam stability exactly and comprehensively.In this thesis, the system investigations of stress, deformation and seepage in-situ observed data for hei he earth core rockfill dam are executed by different methods: firstly based on analysis of the time property and space property, the stress, the deformation and seepage rules of the dam are concluded and the safety status of the dam is given in qualitatively; then using the 3-D finite element simulation back analysis model, tracking the construction and operation of the dam, the real parameters are got, after that the real stress ,deformation and seepage field during different periods are given by real parameters and the safety of the dam is evaluated in quantitatively using the criterions suggested, some key problems such as the possibility of core wall crack ,seepage stability and the stability of upstream and downstream slope are analyzed in detail. The main conclusions are as follows:(1) Based on analysis of the time property and space property, the stress, the deformation and seepage rules of the dam are concluded and explained reasonably, then evaluate the stability of deformation and seepage field using the criterions suggested.(2) The DUCAN-ZHANG E-B model and wetting model Cw ? Dw are developed in the large universal finite element program ABAQUS, and the developed programs are successively used to simulate the dam consolidation of construction and operation.(3) Based on analysis of the deformation rules, the relationship between the deformation and load is build and then a method back-analyze the soil parameters during construction and operation is suggested. which can present the mainly DUCAN parameters, seepage coefficients of core clay and wetting parameters. And with the observation data, the seepagecoefficients of the rockfill and core caly during operation are got using saturation seepage analysis program.(4)3-D finite element consolidation and 2-D stress and seepage analysis are executed using back-anlyzed soil parameters, then the three key problems such as the possibility of core wall crack ,seepage stability and the stability of upstream and downstream slope are analyzed in detail with the criterions suggested in the thesis.(5) An program automatically process in-site observation data of the dam also is also developed.