地下水工隧洞围岩及钢筋混凝土岔管结构数值分析

随着高山峡谷地区大型水电工程的兴建，深埋地下水工隧洞的围岩稳定和内外水压力作用下衬砌应力变形等成为重点关注问题。从围岩开挖支护、围岩衬砌相互作用和钢筋混凝土有限元模拟等方面建立钢筋混凝土岔管段数值分析模型，以蒲石河抽水蓄能电站尾水岔管为例，分析了围岩的应力、变形问题以及混凝土岔管结构配筋和配筋后应力、裂缝开展等问题。围岩分析计算结果表明：在主、岔洞交叉处会产生拉应力，塑性区开展较深，同时主洞靠近岔洞侧和尾水支洞的两侧岩体塑性区也有较大的开展。岔管结构分析计算结果表明：正常运行工况在内水压力作用下岔管结构大部分区域存在拉应力，裂缝较大；检修工况在外水压力作用下仅在主、岔管交叉处存在拉应力区，裂缝较小。

Numerical Analysis on Surrounding Rock and Reinforced Concrete Bifurcation Structure of Underground Tunnels

With the construction of large water-power engineering projects in alpine and canyon area, the stability of surrounding rock and stress deformation of lining under outer and inner water pressure becomes important. The excavation and supporting of surrounding rock, interaction between surrounding rock and lining, behavior of reinforced concrete were modeled. Then the stress and deformation of surrounding rock, reinforcement of lining material, stress and crack in reinforced concrete bifurcation structure were analyzed in the project of Pushihe pumped-storage power station. Calculation result of surrounding rock show that: tension stress zone mainly exist in connection region of main tunnel and bifurcation tunnel, plastic zone developed in connection region and region of main tunnel that adjacent to the bifurcation tunnel, bifurcation tunnel also has plastic zone. Calculation result of bifurcation structure show that: during error-free running work condition most region of the bifurcation structure exist tension stress, crack width is large; during overhaul work condition tension stress only exist in connection region of main tunnel and bifurcation tunnel, crack width is small.