堆石料动力残余应变模型研究

Residual deformation model for rock-fill materials

采用大型静动三轴压缩试验仪,对某面板堆石坝筑坝材料进行了动残余变形试验,研究了砂砾石料和开挖料在循环荷载作用下的残余变形特性及其影响因素。试验资料表明,动荷载作用下第一次循环振动诱发的残余剪应变最大,随着振次增长,剪应变持续增加,在试验设定的振次内,未出现收敛趋势。与之不同,残余体应变在循环荷载作用下有明显的收敛趋势。基于试验结果建立了残余变形与循环振动周次和动剪应变振幅的关系,提出了计算模型。模型共8个参数,均可通过动三轴试验确定,能较好地反映残余应变发展规律。

Large scale triaxial shear tests on rock-fill materialsare performed to study the residual deformation behaviors of rock-fill materials byusingthe large-scale triaxial apparatus. The characteristics of residual deformation of cushion material, excavated material and main rock-fill with two different densities are the focuses of this study. Based on enough test results, it isrevealed that the generated shear strain after the application of the first cycle of loading is the main part of the residual shear strain,and its development relates to the accumulation rate of the residual shear strain as the loading cycle increases. In the set test vibration times, the convergence trend does not appear. In contrast, the rock-fill materials have asymptotic volumetric behaviors under cyclic loading. On the basis of test data,a residual deformation model with eight parameters is proposed, which can well reflect the development of the residual strain. And the parameters can be calibrated by dynamic triaxial tests.