Mechanism analysis and treatment technique of surrounding rock instability for tunnel portal section in weak surrounding rock

作者：Liu Xiao Jun^*; Zhang Yong Xing; Gao Shi Jun; Huang Da; Yang Chao

来源：Yantu Lixue/rock and Soil Mechanics, 2012, 33(7): 2229-2234.

• Fast Lagrangian analysis of continuum
• Guizhou Province
• Mechanism analysis
• Plastic zones
• Shallow and unsymmetrical pressure
• Surrounding rock
• Three dimensional simulations
• Three dimensions
• Treatment techniques
• Tunnel collapse
• Tunnel excavation
• Tunnel portals
• Weak surrounding rocks

Landslide is easy to occur at the tunnel portal section due to the surrounding rock is weak, and besides, many of the tunnels portal section are shallow and under unsymmetrical pressure. The surrounding rock of Ruipo tunnel in Guizhou province of Xiamen-Chengdu expressway is instability when the tunnel excavated shortly. Analysis of three-dimensional simulation in the excavation process of portal section of Ruipo tunnel is conducted by using the fast Lagrangian analysis of continua in three dimensions (FLAC3D). Based on the results of plastic zones in surround rocks, deformations in rock and actual situation on site, the causes of tunnel collapse and support deformation are analyzed. Actual tunnel excavation sequence is optimized by numerical simulation. Then the effective remedy measures are proposed and good results are achieved. The analysis results can provide reference for similar engineering.

• 出版日期2012