An improved numerical manifold method for investigating the mechanism of tunnel supports to prevent large squeezing deformation hazards in deep tunnels. (November 2022)

• Record Type: Journal Article
• Authors: Xu, Xiangyu; Wu, Zhijun; Liu, Quansheng
• Is Part Of: Computers and geotechnics. Volume 151(2022)
• Publication Date: 2022-11
• Subjects: Numerical manifold method -- Deep rock tunnel -- Tunnel support -- Installation timing of tunnel support -- Large squeezing deformation hazard; Engineering geology -- Data processing -- Periodicals; Soil mechanics -- Data processing -- Periodicals; Rock mechanics -- Data processing -- Periodicals; 624.1510285
• DOI: 10.1016/j.compgeo.2022.104941
• Languages: English
• ISSNs: 0266-352X

Abstract

Abstract: To investigate the mechanism of tunnel supports for large squeezing deformation hazards, the explicit cohesive element-based numerical manifold method (ECo-NMM) is extended. First, for modeling the compound effect of the artificial supports and tunnel face, a layer-based tunnel support algorithm is proposed to simulate the interaction between the supports, tunnel face and surrounding rock mass and represent the geometric and mechanical properties of the tunnel supports. Then, to investigate the influence of tunnel support timing, a mapping algorithm is proposed to correlate simulated processes with real excavation processes, based on which the installation timing of tunnel supports is characterized. In addition, a reconstruction algorithm is proposed to illustrate 2D simulation results in 3D. To validate the accuracy and applicability of this improved method, numerical cases are conducted using the developed method, and the predicted results are compared with analytical solutions, test observations and original numerical results. Finally, this improved method is applied to investigate the influence of the tunnel support timing, and the predicted results indicate that the squeezing stress acting on the tunnel supports first decreases and then increases with the continuous increase in the delay in the tunnel support, based on which the tunnel support timing is optimized.