Stress modelling and rock support for hydro-electric water tunnels

水电设施位于不列颠哥伦比亚省基蒂马特东南70公里处，是一个令人印象深刻的 由于它的规模和地理位置的偏远，这是工程上的壮举。这件事的重点是 研究的是两条16公里长的输水隧道，一条正在运营，另一条部分 完成。第一条隧道T1于20世纪50年代竣工，而T2隧道在20世纪50年代部分开挖 20世纪90年代初。该地区多山的地形给岩石支撑带来了挑战 设计时，隧道周围的应力沿隧道路线变化很大。大型 从二维有限元应力确定应力方向和大小的变化 模型和这些结果与现场观察到的破坏机制相一致。建议数 研究有以下目标： 1)通过以下方式进一步评估T2隧道延续段周围的预期应力条件 建立覆盖两条隧道全长的大型三维应力分析模型。 2)合并隧道沿线的预测应力和有关岩性、地下水的数据 流入一种称为贝叶斯网络的概率预测工具。 3)利用开发的贝叶斯网络工具对隧道沿线岩层进行预测。 4)使用地面等级来推荐要维护的适当的主要和最终岩石支架 隧道稳定性，进而提供隧道预期成本和进度方面的指导。

hydro-electric facility located 70 km southeast of Kitimat, British Columbia is an impressive feat of engineering due to both its scale and the remoteness of its location. The focus of this research are two 16 km long water conveyance tunnels, one operational and one partially complete. The first tunnel, T1, was completed in the 1950s, while T2 was partially excavated in the early 1990s. The mountainous topography in the area poses challenges for rock support design as the stresses around the tunnels vary widely along the tunnel alignment. Large variations in stress orientations and magnitudes were identified from 2D finite element stress models and these results corresponded to failure mechanisms observed on site. The proposed research has the following goals: 1) Further evaluate the expected stress conditions around the continuation of the T2 tunnel by constructing a large 3D stress analysis model covering the full length of both tunnels. 2) Incorporate predicted stresses at along the tunnel and data regarding lithology, ground water inflow, and discontinuities into a probabilistic prediction tool called a Bayesian Network. 3) Use the developed Bayesian Network tool to predict ground classes along the tunnel. 4) Use the ground classes to recommend appropriate primary and final rock support to maintain tunnel stability and in turn provide guidance on expected tunnelling costs and scheduling.