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Numerical Simulation of the Rheological Damage Mechanism of a Surrounding Rock Mass with High Ground Stress
(1 Faculty of Engineering, China University of Geosciences (Wuhan), Wuhan 430074; 2 School of Civil and Architectural Engineering,Wuhan University, Wuhan 430072)
Abstract With high ground stress, a tunnel′s surrounding rock reveals rheological behaviors and damage—it may even break up. However, the evolution process of internal damage has not yet been directly observed. Taking the marble mass around the JINPING II Hydropower Station diversion tunnel as a research subject, and based on tri-axial strength test results and data from the analysis of a rheological damage experiment, a numerical model is established to reflect the short-term and long-term strength features of the marble specimen by introducing the parallelbonded stress corrosion model (PSC) into the particle flow numerical simulation method. The tri-axial compressive creep numerical experiments show that the cracking type, cracking direction, distribution characteristics and extension process of the micro-cracks in the marble specimen present various patterns under different stress states, and the rheological damage effect of the marble will gradually decrease with an increase of the confined stress. Based on an analysis of the rheological damage characteristics of the marble specimen, a finite element (FEM) numerical model of the Jinping II Hydropower station diversion tunnel was built and the rheological damage evolution mechanism of the surrounding rock during tunnel excavation was elucidated.
Abstract：
With high ground stress, a tunnel′s surrounding rock reveals rheological behaviors and damage—it may even break up. However, the evolution process of internal damage has not yet been directly observed. Taking the marble mass around the JINPING II Hydropower Station diversion tunnel as a research subject, and based on tri-axial strength test results and data from the analysis of a rheological damage experiment, a numerical model is established to reflect the short-term and long-term strength features of the marble specimen by introducing the parallelbonded stress corrosion model (PSC) into the particle flow numerical simulation method. The tri-axial compressive creep numerical experiments show that the cracking type, cracking direction, distribution characteristics and extension process of the micro-cracks in the marble specimen present various patterns under different stress states, and the rheological damage effect of the marble will gradually decrease with an increase of the confined stress. Based on an analysis of the rheological damage characteristics of the marble specimen, a finite element (FEM) numerical model of the Jinping II Hydropower station diversion tunnel was built and the rheological damage evolution mechanism of the surrounding rock during tunnel excavation was elucidated.
SUN Jin-Shan- 1 Zuo-Chang-Qun- 1 Jiang-Qing-Hui- 2 Xie- Ni- 1 Jiang- Nan
.Numerical Simulation of the Rheological Damage Mechanism of a Surrounding Rock Mass with High Ground Stress[J] MODERN TUNNELLING TECHNOLOGY, 2016,V53(5): 35-42
2016, Vol. 53 