Numerical Modeling of Stress Disturbance Characteristics during Tunnel Excavation. (28th April 2020)

• Record Type: Journal Article
• Authors: Zhu, Zeqi; Sheng, Qian; Zhang, Yumin; Liu, Shiwei
• Other Names: Riccio Aniello Academic Editor.
• Is Part Of: Advances in materials science and engineering. Volume 2020(2020)
• Publication Date: 2020-04-28
• Subjects: Materials science -- Periodicals; Materials science; Periodicals; 620.11
• DOI: 10.1155/2020/4508905
• Languages: English
• ISSNs: 1687-8434

Abstract

Abstract : The stress state and principal stress axis changes of the stress-field tensor are analyzed during the advancement of a tunnel face on the basis of a given case study of the Jinping II Hydropower Station in China. First, the prevailing pole diagram in geology is used to illustrate the rotation of the stress axes as the tunnel face advances. The results show that the orientation adjustments of principal stresses in different positions near the tunnel boundary share common characteristics. The major and minor principal stress axes ahead of the tunnel face will rotate to intersect with the excavation surface at an angle, with the intermediate principal stress axis being almost parallel to the excavation surface. Furthermore, the stress triaxiality that is commonly used to indicate the deformation and damage of metal materials is introduced to describe the stress state change of the excavation-induced stress. The stress triaxiality is found to represent the stress state change due to the variation in both the magnitude and orientation of the stress-field tensor. According to the physical meaning and the change law of the stress triaxiality, stress disturbance during tunnel excavation can be divided into four stages, and the stress disturbance zone is divided into a strong disturbance zone and a weak disturbance zone. The disturbance characteristics of different stages and the distribution patterns of various zones are analyzed, which may be useful for practical application in the design and construction of rock tunnels.