Viscoelasto-plastic rheological experiment under circular increment step load and unload and nonlinear creep model of soft rocks
- 264 Downloads
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 function H of viscidity coefficient. The model can describe the accelerated creep of soft rocks since the nonlinear damaging evolvement variable D of 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.
Key wordsrheological experiment nonlinear creep damaging hardening soft rocks
Unable to display preview. Download preview PDF.
- YUAN Hai-ping. Study on the rheologic fracture of jointed rock mass under inducing condition and its engineering application [D]. Changsha: Central South University, 2006. (in Chinese)Google Scholar
- SUN Jun. Rock rheological mechanics and its advance in engineering applications [J]. Chinese Journal of Rock Mechanics and Engineering, 2007, 26(6): 1081–1106. (in Chinese)Google Scholar
- CHEN Yuan-jiang, PAN Chang-liang, CAO Ping, WANG Wen-xing. A new mechanical model for soft rock rheology [J]. Rock and Soil Mechanics, 2003, 24(2): 209–214. (in Chinese)Google Scholar
- XU Wei-ya, YANG Sheng-qi, CHU Wei-jiang. Nonlinear viscoelasto-plastic rheological model(Hohai model) of rock and its engineering application [J]. Chinese Journal of Rock Mechanics and Engineering, 2006, 25(3): 433–447. (in Chinese)Google Scholar
- JIN Yao, SUN Xun-fang, SUN Ya-fang, DENG Yong, LIU Hong-jie, TU Yong. Creep law with effect of loading history [J]. Journal of Mechanical Strength, 2001, 23(2): 206–208. (in Chinese)Google Scholar
- ZHAO Yan-lin, CAO Ping, WEN You-dao, WANG Yi-xian, CHAI Hong-bao. Elastovisco-plastic rheological experiment and nonlinear rheological model of rocks [J]. Chinese Journal of Rock Mechanics and Engineering, 2008, 27(3): 477–487. (in Chinese)Google Scholar