地下厂房工程
Powerhouse Excavation — Rock-Anchored Crane Beam Construction
Gu, the main powerhouse cavern is a massive underground excavation — 140 meters long, 25 meters wide, and 52 meters high. That's comparable to a 15-story building placed underground. The stability of the rock mass during and after excavation is absolutely critical. Walk me through your excavation sequence and support design.
谷工，主厂房洞室是一个巨大的地下开挖——140米长、25米宽、52米高。 堪比一座15层大楼放到地底下。开挖中和开挖后岩体稳定绝对关键。给我讲讲 开挖顺序和支护设计。
谷工: We're using a top-down bench excavation method with 8 benches total. First, we excavate the top heading — a 9-meter high arch-shaped section along the full 140-meter length. This is the most critical stage because the arch is self- supporting once formed. Each drill-and-blast round pulls 3.5 meters. After mucking out, we install the primary support immediately — 6-meter long, 32 mm diameter rock bolts at 1.5-meter spacing in the arch, plus a 150 mm thick layer of steel-fiber-reinforced shotcrete applied with a robotic sprayer.
用自上而下的台阶开挖法、共8个台阶。首先开挖顶拱导洞——沿全长140米、 9米高的拱形断面。这是最关键的一步因为拱一旦成型是自承的。每循环钻爆 进尺3.5米。出渣后立即安装初期支护——拱部6米长、32 mm直径锚杆、间距 1.5米，加150 mm厚钢纤维喷混凝土、用湿喷机械手施工。
The rock-anchored crane beams are installed at bench 3 level — about 18 meters below the arch crown. These are the most critical structural elements in the powerhouse. They support the two 250-ton overhead cranes that will handle the turbine and generator installation.
岩锚吊车梁在第三台阶层安装——大约拱顶以下18米。这是厂房里最关键的 结构元素。它们支撑两台250吨桥式起重机，用于水轮机和发电机安装。
The crane beam anchors — that's where the loads go directly into the rock. What's the anchor design?
吊车梁锚杆——载荷通过它们直接传进岩体。锚杆设计是什么？
谷工: Each beam is anchored with two rows of prestressed rock bolts — the upper row inclined 25° upward and the lower row inclined 20° downward. Each bolt is 12 meters long, 36 mm diameter, high-strength steel Grade 1080. The design pre-tension is 500 kN per bolt. The bolts are fully grouted after tensioning. We're proof-load testing 5% of the anchors — that's 6 bolts per beam — to 150% of the design load (750 kN) to verify the bond strength in the rock. So far all tests have passed with zero creep.
每根梁用两排预应力锚杆锚固——上排向上倾斜25°、下排向下倾斜20°。每 根锚杆长12米、直径36 mm、高强钢1080级。设计预拉力每根500 kN。张拉后 全孔灌浆。抽检5%锚杆做验证试验——每根梁6根——拉到150%设计荷载（750 kN）验证岩体粘结强度。目前全部试验通过、零蠕变。
Powerhouse Completion — Preparation for Turbine-Generator Installation
谷工，厂房开挖完成、桥式起重机已调试通过并做了负荷试验。现在要准备 1号机安装。第一个要装的部件是蜗壳。预埋件和水轮机坑怎么样了？
今早用全站仪参照厂房控制网测量了水轮机坑。中心线坐标：与设计偏差北 向+1.5 mm、东向-0.8 mm——全部在±2 mm指标内。坑底高程在设计+2 mm内。 全部预埋冷却水管、排水管和电线管已安装并打压试验。座环的预埋地脚螺栓 已就位、位置已验证。
我也在水轮机坑墙壁上建立了机组中心线标记——4个永久基准靶标，用于从 蜗壳到水轮机轴再到发电机的每一个部件的对中。对中基准从厂房主控制网传 递、闭合精度0.3 mm。
蜗壳下周到。在工厂已经预组装并打了匹配标记。4个分块在坑内用螺栓拼 装焊接。焊后灌外包混凝土之前要做1.5倍设计压力的水压试验。蜗壳周围的 混凝土是整个厂房里钢筋最密集的浇筑——要确保混凝土浇筑过程中预埋件不移 位。