白鹤滩水电站拱坝及坝肩加固效果分析及整体 安全度评价

 白鹤滩水电站拱坝左侧坝肩断层及层间、层内错动带发育，拱推力作用下易发生剪切变形。坝基柱状节理层发育，变形模量等力学指标相对较低，表现出显著的各向异性力学特性。由于以上地质缺陷的影响，设计采取沿拱推力方向设置抗剪洞及扩挖坝基处柱状节理层岩体设置垫座的工程处理措施，以期对坝肩、坝基岩体的抗剪、传力等进行改善。采用三维非线性数值分析方法，根据实际地质信息建立三维数值模型，模拟白鹤滩中坝址主要地质现象及相关工程措施，通过坝肩、坝基岩体及坝体的应力、位移对比，定量分析主要地质缺陷的影响以及工程处理措施的效果。采用超载法、强度折减法及点安全系数法评价下坝线拱坝的安全度，为该水电站坝线比选提供技术依据和科研成果支撑。

REINFORCEMENT EFFECT ANALYSIS AND GLOBAL SAFETY EVALUATION OF ARCH DAM AND ABUTMENT OF BAIHETAN HYDROPOWER STATION

As faults，inner layers and interlayer shear bands widely develop in the left dam abutment of Baihetan Hydropower Station，and the fault F33 directly conjoins with the left dam abutment，so，shear deformation easily occurs under the thrust of arch dam. The mechanical indexes of dam foundation such as deformation modulus are relatively small and the anisotropy of dam foundation is obvious due to the development of columnar joints layers. In order to reduce the influence of these geological defects，some engineering measures are taken when designing，such as setting anti-shear tunnel along the direction of arch thrust，the cushion to the rock mass of dam foundation，etc.. These measures will improve the shear and transmission force mode of abutment and foundation to some extent. 3D nonlinear numerical method is applied and 3D numerical model based on geological information is built to simulate certain geological phenomena and related engineering measures in middle dam site of Baihetan Hydropower Station. The safety degree of the downstream dam line is evaluated by overloading method，strength reduction method and point safety factor method. The results obtained by these methods will play a role of support to technical basis and scientific research achievements for choosing dam line.