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针对顺向高边坡、偏压隧洞工程中岩土参数不确定、地质条件特殊及工况复杂等问题,以涔天河水库扩建工程(#1泄洪洞出口顺向高边坡开挖与偏压隧洞掘进、支护)为例,在描述出口边坡地形、地貌及工程地质条件的基础上,建立了相应的三维数值计算模型。即基于弹塑性理论考虑岩土体的时效特性,在FLAC3D平台上进行了二次开发与数值计算。分析结果表明,围岩和管棚的变形量较小,出口段管棚支护方案基本能维持围岩稳定,但顺向边坡的变形量较大,需预防边坡表层发生破坏;紧邻放空洞未出现贯通塑性屈服区,但管棚两侧应力分布不对称、内侧拱脚应力较大,可能会造成局部失稳,进而对原有工程开挖、支护方案进行了合理优化,可为类似边坡、洞室的施工建设提供安全判据和参考。
In view of the problems such as uncertain geotechnical parameters, special geological conditions and complex working conditions in the forward slope and the bias tunnel project, the excavation and bias of the high slope along the Sui Tian River Reservoir Extension Project Tunneling and supporting) as an example, the corresponding three-dimensional numerical model is established on the basis of describing the topography, geomorphology and engineering geological conditions of exit slope. That is to say, based on the elasto-plastic theory, the time-dependent characteristics of rock and soil are considered, and the secondary development and numerical calculation are carried out on the FLAC3D platform. The analysis results show that the deformation of surrounding rock and pipe shed is small, and the support scheme of pipe shed protection in the exit section can basically maintain the stability of surrounding rock. However, the deformation of the forward slope is relatively large, so it is necessary to prevent the slope surface from being damaged. The hole does not appear to penetrate the plastic yield zone, but the stress distribution on both sides of the pipe shed is asymmetric and the internal arch foot stress is large, which may result in partial instability, and then the original project excavation and support plan is optimized reasonably. Similar to the slope, construction of the cavern to provide safety criteria and reference.