岩石隧道之模組化分析-多孔隧道之交互影響應用

Abstract

相鄰隧道的開挖可能造成原本已經穩定隧道的破壞，對於隧道支撐之設 計具有相當決定性的影響。本研究即針對相鄰多隧道之間的交互影響做一 系列之探討。本研究首先擬出岩石隧道之回饋分析模組化架構，建立一系 列之分析模組，以供隧道開挖分析模擬之用，進而利用此架構探討相鄰隧 道間之交互影響。研究內容包含單隧道與多隧道之間收斂變形、塑性區、 與支撐應力的探討，以及隧道間距的的影響等問題。由研究的結果發現， 相鄰隧道施工，使導坑產生新的收斂變形與支撐應力變化，塑性區亦因此 而擴大，顯示相鄰隧道開挖的確會對已完工隧道造成影響。就隧道之支撐 應力所受的影響，若考慮到相鄰隧道施工的影響，有可能會造成原本已達 穩定之隧道支撐因鄰近多孔隧道之交互作用而造成破壞。在隧道間距之大 小的影響上，假想增大兩主坑的間距予以考量由模擬分析發現，增加相鄰 隧道間距，在收斂變形方面，將使導坑所受主坑開挖之影響越來越小，而 對先已完工隧道側壁應力之增加量亦逐漸不顯著。就相鄰多孔隧道開挖順 序的影響上，採用較對稱方式進行之隧道開挖順序，可以促使收斂變形與 支撐應力變化較為漸進均勻。就多孔隧道的支撐設計而言，對相鄰隧道的 交互影響，宜予以審慎評估。 Tunnel excavation may result in the failure of an adjacent completed tunnel.Interactions of adjacent tunnels play an important role on the stability of tunnel-support. This thesis aims to investigate the interaction between adjacent multiple tunnels. First, the thesis proposes a methodology for feed- basced analysis of rock tunnels. The methodology, then, is applied on studying the problems of multiple-tunnel interaction. These problems include(1)the difference between single-tunnel analysis and multiple-tunnel analysis; (2) the influence of tunnel-spacing; (3) the influence of excavation sequence of multiple tunnels. The results of numerical simulations reveal several findings. The excavation of adjacent tunnel(s) may result in the deformation and support-stresschange of a completed tunnel. By increasing the tunnel spacing, the interaction between adjacent multiple tunnels is reduced;both the changes in defor-maion and support-stress due to adjacent tunnel-construction will decrease. The sequence of tunnel- excavation also affects the interaction between adjacent multiple tunnels. In conclusion, the interaction between multiple tunnels is important, and should not be ignored in the design of the support of multiple tunnels.