天花板拱坝左岸坝肩窑洞式开挖设计及研究

Design and Study for the Left Abutment Cave-typed Excavation of Tianhuaban Arch Dam

天花板拱坝左岸坝肩岩体为白云岩且边坡地形陡峻,拱坝基础面上游侧嵌入岩体较深,下游侧呈倒喇叭形、山体相对单薄,拱坝建基面嵌入岩体相对较浅,另外坝顶高程以上布置机械施工道路困难,经坝肩开挖形式的研究分析,拱坝左岸坝肩采用窑洞式开挖。实践证明该开挖型式具有开挖范围小、边坡高度低、开挖及支护工程量省、保护边坡生态环境和提高坝肩稳定等优点。

The rocks in the left abutment of Tianhuaban Arch Dam are dolomite. In the upstream side of the abutment, the terrain is steep and the abutment embeds deep into rock, but in the downstream side, the terrain is an inverted trumpet shape with relative thin mountain and the abutment embeds shallow into rock. Arranging construction machinery above the crest is also difficult. After abutment excavation analysis, the cave-typed excavation is adopted for the left abutment. The practice shows that the excavation have advantages of smaller excavation ranges, lower slope height, less excavation and support, protecting ecological environment of slope and improving slope stability.