白鹤滩水电站坝基加固方案评价

Dam foundation reinforcement analysis of Baihetan hydropower station

白鹤滩水电站是我国继三峡、溪洛渡之后开展前期工作的又一座千万千瓦级以上的水电站。坝基区柱状节理岩体发育,其力学指标相对较低并表现出显著的各向异性力学特性,拟采用垫座方案减少破碎柱状节理岩体和部分结构面对拱坝稳定性和安全性的影响。根据精细的地质信息建立三维数值模型,基于微结构张量方法开发了柱状节理岩体横观各向同性弹塑性本构模型。通过视柱状节理岩体为各向同性和各向异性模型的对比研究分析各向异性的影响;对比分析了白鹤滩水电站坝基岩体加固前后坝体一坝基的位移和应力分布情况,以评价加固方案的可行性;采用水压力超载法对大坝一坝基的整体稳定性进行了分析。本研究可为白鹤滩水电站可行性研究终期阶段提供技术依据和科研支撑。

Baihetan hydropower station with an installed capacity more than 10,000MW is the third largest hydropower station in China after the Three Gorges project and Xiluodu project. At its dam site have developed columnar jointed rocks that are anisotropic materials with lower mechanical strengths. To reduce the negative influence of these rocks and faults a reinforcement scheme was proposed for stability and security of the dam. Based on the geological data, an accurate three-dimensional numerical model was developed, and a transversely isotropic elastic-plastic constitutive model was adopted for describing the mechanical behaviors of columnar jointed rocks. This paper discusses the influence of anistropy using the simulations by the transversely isotropic constitutive model and the isotropic constitutive model, and presents a comparative analysis on deformation and stress distributions in the dam and foundation in the schemes of reinforcement and no reinforcement. And the overall stability of dam-foundation is evaluated by using water pressure overload method. This study provides a technical support to the final-stage feasibility study on Baihetan hydropower station.