The Stability Analysis of a Three-Hole-Tunnel Excavation in a Specific Jointed Rock Masses with a variety of Tunnel Shapes Using DDA Method

• Main Authors: TSUNG-FU HUANG, 黃宗甫
• Other Authors: Chihsen T. Lin
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/26898645844300809605

碩士 === 國立高雄第一科技大學 === 營建工程所 === 93 === The numerical method of Discontinuous Deformation Analysis (DDA) is adopted in this research. Its theory was originally developed by Dr. Gen-hua Shi and published in 1989. The DDA method is capable of completing the direct deformation and stress analysis in the jointed rock masses and simulating the joint behavior of the rocks under excavations due to allowing the separation, compression, rotation and collision between the DDA blocks. This research employs the newly developed DDA program DDA-2005. The program includes the simulation of the viscous damping in blocks in order to avoid the reflection of the contact energy between the blocks and boundary blocks back to the area of the analysis when the number of the time step is increased to a certain large amount. The energy basically would cause the larger stresses in the simulation than the ones in the field. Although the rock bolts are stalled in the simulation, the simulation result still shows that the rocks around the excavated tunnel would collapse. It is not a comparable result with the field situation. This research adopted the profile of the Ping-Lin three-hole tunnel in Pei-I Highway in order to investigate the influence of the various tunnel profiles to the stress distribution around the excavated area and the newly developed function of the viscous layer. The analysis result shows that the viscous damping layer at the boundary is able to absorb the reflecting energy to the area of the analysis therefore the more realistic simulation of the tunnel excavation using the DDA method could be obtained.