适应柱状节理玄武岩坝基的特高拱坝结构研究

Study on the super high arch dam structure adapting to the columnar basalt base

白鹤滩水电站坝址区柱状节理玄武岩发育,其岩芯破碎,完整性较差,变形模量等力学指标相对较低,还表现出各向异性及开挖后易松弛的特性。白鹤滩水电站是首次将柱状节理玄武岩应用于高拱坝坝基,为研究特高拱坝适应基础岩体的力学特性,本文提出了拱坝扩大基础的结构形式。应用三维有限元方法,计算研究了扩大基础受力机理及效应,并研究柱状节理玄武岩松弛的敏感性,论证了拱坝扩大基础适应柱状节理玄武岩坝基特性的能力。

The columnar basalt rock develops in the dam site area of Baihetan hydropower station.Its deformation modulus is relatively low owing to its poor integrity.Especially,it shows the characteristics of anisotropy and easy relaxation after excavation.It is the first time that the columnar basalt rock is chosen as the base of super high arch dams at the site of Baihetan Hydropower Station.The structural form of expanded foundation was put forward for the design of the super high arch dam to adapt to the characteristics of the columnar basalt at the base.By applying the three-dimensional finite element method,the thrust force expanding mechanism and the effect of expanded foundation were studied,and the effect of the relaxation of the columnar basalt on the arch dam was also studied.The capability of the expanded foundation of the arch dam to adapt to the foundation characteristics of the columnar basalt rock layers was demonstrated by computation results.