The nonlinear safety is very important for the system of arch dam and its foundation since it is statically indeterminate structure and the geomechanical model test is effective method to evaluate the stability of arch dam. The analysis of failure process for a double-curvature arch dam with 167.5-meter-high, located in the northwest of China, has been carried out based on overload method. A quantitative method for determining the safety factor of initial nonlinear deformation of model test is proposed based on the Pearson product-moment correlation coefficient. Through the defromation evolution of all monitoring points, the nolinear safety has been determined. Then it is verified by acoustic emission data. By comparing the model test results of arch dam with other arch dams, the overall stability and safety of narrow valley arch dam is higher, and its failure mode is more dominated by foundation, while that of wide valley arch dam is more dominated by dam. The safety factor of initial nonlinear deformation, which has the same meaning as the control index of compressive stress safety of arch dam in the design specification, correspond to the compressive stress failure of the downstream dam toe.

非线性安全对拱坝系统及其基础非常重要，因为它是静态不确定的结构，而岩土力学模型试验是评估拱坝稳定性的有效方法。基于过载法，对我国西北部高167.5米的双曲拱坝进行了破坏分析。基于皮尔逊积矩相关系数，提出了一种确定模型试验初始非线性变形安全系数的定量方法。通过所有监测点的演化演变，确定了非线性安全性。然后通过声发射数据进行验证。通过比较拱坝与其他拱坝的模型试验结果，窄谷拱坝的整体稳定性和安全性更高，它的破坏模式主要由基础决定，而宽谷拱坝则主要由大坝决定。初始非线性变形的安全系数与设计规范中拱坝的压应力安全控制指标具有相同的含义，对应于下游坝脚趾的压应力破坏。