Triaxial Test Research On Rock Filling Creep Behavior Of Rock Fill DAM

With the improvement of Chinese economy，the empoldering of water andelectricity entered a unprecedented climax. Among different types of dam，the rockfilldam has been paid more and more attention because of its outstanding advantages，Rockfill dam more than200metres high is a development trend in the world.Through the past already built the settlement of engineering data analysis，the laterincreases deformation of high dam rockfill is more obvious，the safety of the dam hasimportant influence，therefore people pay more attention on the rockfill creepcharacteristics of a high rockfill dam design and construction process. In practice ofengineering，in addition to the prototype observation of high rockfill dam， it isnecessary included in the pile of rock body creep effect. How to make a reasonablemodel to describe the dam body long-term creep of stone and the research of theparameters for the model，become the problem that urgent need solved in the designand construction.In this paper，analyses of rockfill creep model and creep deformation mechanismare reviewed by reading massive research papers and reports. Based on the laboratorytest，use the test equipment which adapts long-term and large long-term deformationhigh pressure， expand experimental study of the long-term creep deformationcharacteristics of the LiangHeKou core rockfill dam.In order to have a morecomprehensive understanding on the rockfill creep deformation characteristics andmechanism，and establish a analysis model which can reflect the actual situation ofthe dam body deformation on the base of the test data collection and analysis，providereliable creep parameters.Based on the analysis of the LiangHeKou core rockfill dam in the process，mainwork has been completed in the following：(1) Put forward a new kind of loading method：equivalent stress ratio loadingmethod. Illustrates its different with equivalent confining pressure loading method，it’s considered that equivalent stress ratio loading method is more fitter withengineering practice of rockfill’s stress state，so it can better reflect the long-termdeformation characteristics of rockfill.(2) Analyzes the rules of axial strain and volume strain in different loadingmethod,and explore the relationship between final creep variable and confiningpressure，stress level，stress ratio. Found that in lower surrounding pressure and lower stess ratio，sample appeared side shrink phenomenon，in higher confining pressure andhigher stress ratio，sample appeared side bilge phenomenon.(3) Establish axial creep model and volume creep model in two different loadingmethod based on the experience constitutive equation：using logarithm function todescribe the relationship between axial creep and time，using the power function todescribe the relationship between volume creep and time，and presents a method todetermine the model parameters. Verify the rationality of the creep model through thecomparison of experiment data point and creep model fitting curve，and consideredthat the model from equivalent stess ratio loading method is more suitable for rockfillcreep under the state of high confining pressure.