Viscoelasto-plastic rheological experiment under circular increment step load and unload and nonlinear creep model of soft rocks
Viscoelasto-plastic rheological experiment under circular increment step load and unload and nonlinear creep model of soft rocks
复制标题
DOI：
10.1007/s11771-009-0082-7
复制
发表时间：
2009-06
影响因子：
--
通讯作者：
Yanlin Zhao;P. Cao;Weijun Wang;W. Wan;Ye-ke Liu
中科院分区：
文献类型：
--
作者：
Yanlin Zhao;P. Cao;Weijun Wang;W. Wan;Ye-ke Liu
金川三矿软矿岩的粘弹塑性蠕变试验是在循环增量阶梯加载和卸载条件下进行的。实验数据按照瞬时弹性应变、粘弹性应变、瞬时塑性应变和粘塑性应变进行分析。结果表明，随着蠕变应力的增大，瞬时变形模量呈增大趋势；软岩增强了在循环过程中多层次加卸载过程中抵抗瞬时弹性变形和瞬时塑性变形的能力。对于JC1099试件，粘弹应变与粘塑性应变之比在3.15~6.58之间变化，整体上随着应力的增加，该比值有减小的趋势；蠕变变形在低应力水平下趋于稳定状态；软岩蠕变通常体现在高应力水平下的加速蠕变特性。引入损伤变量和硬化函数，建立了软岩非线性蠕变模型，用粘度系数的非线性硬化函数H来描述衰减蠕变。该模型引入了岩石变形参数的非线性损伤演化变量D，可以描述软岩的加速蠕变。非线性蠕变模型中的均匀蠕变方程可以描述软岩蠕变的三个阶段。将该非线性蠕变模型应用于金川三矿矿岩蠕变实验，非线性蠕变模型曲线与实验数据吻合较好。
The viscoelastic-plastic creep experiments on soft ore-rock in Jinchuan Mine III were performed under circular increment step load and unload. The experimental data were analyzed according to instantaneous elastic strain, visco-elastic strain, instantaneous plastic strain and visco-plastic strain. The result shows that instantaneous deformation modulus tends to increase with the increase of creep stress; soft rocks enhance the ability to resist instantaneous elastic deformation and instantaneous plastic deformation during the multi-level of load and unload in the cyclic process. In respect of specimen JC1099, the ratio of visco-elastic strain to visco-plastic strain varies from 3.15 to 6.58, and the ratio has decreasing tendency with stress increase as a whole; creep deformation tends to be a steady state at low stress level; soft rocks creep usually embodies accelerated creep properties at high stress level. With the damaging variable and the hardening function introduced, a nonlinear creep model of soft rocks is established, in which the decay creep is described by the nonlinear hardening functionHof viscidity coefficient. The model can describe the accelerated creep of soft rocks since the nonlinear damaging evolvement variableDof deformation parameter of rocks is introduced. Three stages of soft rocks creep can be described with the uniform creep equation in the nonlinear creep model. With this nonlinear creep model applied to the creep experiments of the ore-rock of Jinchuan Mine III, the nonlinear creep model’s curves are in good agreement with experimental data.