Intelligent method for parameters optimization of cable in soft rock tunnel base on longitudinal wave velocity. (March 2023)

• Record Type: Journal Article
• Authors: Li, Gan; Zhu, Chun; He, Manchao; Zuo, Yujun; Gong, Fengqiang; Xue, Yiguo; Feng, Guangliang
• Is Part Of: Tunnelling and underground space technology. Volume 133(2023)
• Publication Date: 2023-03
• Subjects: Support optimization design -- P-wave velocity -- Joint density -- Anchor support -- Neural network; Tunneling -- Periodicals; Underground construction -- Periodicals; Tunnels -- Periodicals; Underground areas -- Periodicals; 624.193
• DOI: 10.1016/j.tust.2022.104905
• Languages: English
• ISSNs: 0886-7798

Abstract

Highlights: The density of structural plane highly correlates with the P-wave velocity. Deformation prediction method considering wave velocity is established. Support design combined with wave velocity is an accurate method. Abstract: With the rapid development of the tunnel project, the problem of soft rock tunnel support has become increasingly prominent. The prestressed anchor support method has made great progress in theory and practice, but the research on its quantitative design is less. The optimization design methods need improvement to meet specifications. This paper uses surrounding rock wave velocity and related geological conditions to further enhance the support optimization model. The joint density corresponding to different wave velocities is analyzed, and the DFN (discrete fracture network) is inserted into the numerical model for simulation. To ensure the accuracy of the calculation, similar material simulations and engineering measurements are compared and analyzed. Deformation of the surrounding rock with different support parameters is predicted and analyzed using a neural network and a database formed by numerical simulation calculation. The results show a linear relationship between the P-wave velocity of rock mass and the structural plane density of the surrounding rock. Then, under the influence of the structural plane and without prestressed anchor support, the surrounding rock produces large asymmetric deformation, and the damaged area is extensive. The surrounding rock also has asymmetric deformation with prestressed anchor support, but the deformation value and plastic area are small. The density of the structural plane, the burial depth of the tunnel, and the length of the anchor cable are the main factors controlling the surrounding rock. With an increase in tunnel burial depth, the deformation of the surrounding rock linearly increases. The reduction of the P-wave velocity of surrounding rock will also significantly impact the deformation of surrounding rock. An increase in anchor cable length has a significant control effect in the initial stage, but the control effect slows down with the continuous increase of anchor cable length.