Study On Creep Behavior And Creep Physical Model Of Rockfill Through Triaxial Creep Test

Rockfill dam has been widely used because of its unique advantages, the proportion of highrockfill dam in the world is increasing rapidly, no doubt it is of great significance to study thedeformation characteristics of the rockfill dam after completion. The creep behavior of rockfill isone of the important factors that cause the long-term deformation of rockfill dam, and laboratorycreep test is a major ways of study of rockfill creep.First of all, it summarized several common methods of study change rules of rockfill creepthrough the analysis of literature, and compared the advantages and disadvantages of eachmethods, also analyzed the creep mechanism of rockfill materials. This paper use SR-4largehigh-pressure triaxial creep apparatus through laboratory creep test to studying the creep ofrockfill materials, introduced the experiment principle and experiment steps in detail, andspecified the starting time of creep test and the Judgment standard of deformation steady.Secondly, There are three different loading modes such as the single-stage loading of theconfining pressure is constant, the multi-stage loading of the confining pressure is constant andthe proportional loading to design the laboratory creep test, combined with the engineeringproperties of the major rockfill material and the bedding material of Shangzhai reservoir and themixture of Xiaolangdi water power station, it has analysed the rheological law from three aspectsrespectively which are total strain, creep strain and creep rate, and it has found out that there is alinear relation between the creep strain and the time in log-log coordinate, and their rate is also,also it has analysed the different influences and its reasons to the long-term deformations of thesamples between the single-stage loading of the confining pressure is constant text and themulti-stage loading of the confining pressure text.At last, the final parametric of power function creep model form a (t)btdrew by IWHR had been determined based on the rheological law of the laboratory creep test, and gotexpression of creep physical model under three different loading modes, then calculated themodel parameters according to experimental data, and compared the imitative effect. Resultsshow that the effect of simulating the axial creep at low stress levels or small confining pressure is better, the effect of simulating the volumetric creep at small confining pressure under themulti-stage loading of the confining pressure is constant and the proportional loading is better.Expect to use these expressions of creep physical model to predict creep deformation ofrockfill dam, solving practical engineering problems.