关键词: 蚀变带, 地质缺陷, 坝基处理, 拱梁分载法, 三维非线性有限元法

Abstract: The maximum height of the concrete double-curvature arch dam of Yangfanggou hydropower station is 155 meters. Fault f₂₇ and alteration zone are developed on the left bank of dam foundation, and faults f₅₄₂, f₅₆₂ and alteration zones are developed on the right bank of dam foundation. The strength of faults and alteration zones is low. In order to enhance the integrity and uniformity of the dam foundation, increase its bearing capacity and reduce its deformation, a comprehensive treatment plan is adopted, which is a combination of backfill reinforced concrete after trench excavation, placement of foundation reinforcing mesh, strengthened and denser consolidation grouting, consolidation grouting with cover weight through shallow approach pipe, strengthened and denser curtain grouting, adjustment of dam foundation drainage, addition of stress deformation and seepage monitoring, and et al. By use of archcantilever method and 3D nonlinear finite element method, the reinforcement effect for the geological defects in dam foundation is calculated and analyzed.

Key words: alteration zone, geological defect, dam foundation treatment, arch-cantilever method, 3D nonlinear finite element method