高拱坝工程基础地质及地形条件的不对称是威胁拱坝安全的重要问题。以白鹤滩高拱坝作为工程实例，通过地质力学模型试验重点研究基础不对称的高拱坝应力、变形及破坏模式的特点。针对初始方案和改进后方案分别建立三维数值模型，并进行弹塑性有限元超载计算。对比分析两方案坝体变形、坝肩应力分布、局部和整体稳定性等的不同，并结合试验现象，分析和评价针对基础不对称性的改进措施的加固效果及加固机制。结果表明：体形不对称性设计及基础加固的协同作用能有效改善坝体变形对称性、坝肩应力状态和传力效果，并提高拱坝-地基系统的整体稳定性。白鹤滩拱坝不对称性问题的研究对深入高拱坝设计优化和工程加固的认识具有重要意义。

The geological and topographical asymmetries of high arch dam foundations are essential problems which threaten the arch dam safety. Based on Baihetan arch dam engineering, a geomechanical model test is conducted to particularly evaluate the characteristics of the high arch dam with an asymmetrical foundation, from the respects of states of stress and deformation of the dam and its failure modes. Three-dimensional numerical simulations are built on both original and improved design schemes, based on which elastic-plastic finite element analysis is conducted. A comparison is then made between two sets of results in terms of dam deformation, stress distribution in dam abutment, local and global stabilities of the structure. The actual effect and reinforcement mechanism of the design optimization and reinforcement measures, adjusted to those existed asymmetries of dam foundations, are evaluated by combining with experimental results. It is shown that the optimization of dam shape and foundation reinforcement act synergistically to improve the dam deformation, state of stress and transmission of force in dam abutment area, and global stability of the dam-foundation system. The research of Baihetan arch dam asymmetry problem is significant to deepen the comprehension of optimization design and engineering reinforcement especially for high arch dams.