锦屏一级拱坝坝高为305 m,是世界上最高的拱坝。但是,其坝基岩性较差,f5、f8等断层在建基面出露,基础严重不对称等地质复杂性给锦屏一级拱坝的极限承载力分析评价带来很多不确定性。基于变形加固理论,使用三维非线性有限元程序TFINE,采用直接法和正倒垂测点监测值反演蓄水期坝体混凝土弹性模量和基础变形模量,并验证反演参数在锦屏一级蓄水期预测和极限承载力分析中的适用性。使用反演参数,对坝体正常运行的应力、位移进行仿真分析;采用屈服区、不平衡力、塑性余能范数、整体稳定性安全系数等指标,基于工程类比法,全面评价锦屏一级拱坝的极限承载力。对比反演参数和设计参数的计算结果,验证了设计参数的可靠度。结果表明,锦屏一级拱坝起裂安全系数K1为2倍超载,极限承载安全系数K3为8倍超载,锦屏一级拱坝具有较高的极限承载力,整体稳定性是有保证的。
It is known that Jinping-I arch dam is the highest arch dam in the world with a height of 305 m. However, the dam foundation lithology is quite poor due to f5, f8 and other faults exposed on the construction base layer. In addition, the foundation is highly asymmetric. Hence, the evaluation of the ultimate bearing capacity of Jinping-I arch dam cannot reach an agreement due to the geological complexity. Based on the deformation reinforcement theory and 3D nonlinear FEM program T-FINE, the concrete elastic modulus and dam foundation deformation modulus during impounding period are inverted using a direct method and values of the forward inverted plumb monitoring stations. Moreover, the validity and feasibility of the inversion parameters are verified in the impoundment period prediction and the ultimate bearing capacity analysis. The stress and displacement of dam body under normal conditions are simulated with the inversion parameters. Based on project analogy method, the ultimate bearing capacity of Jinping-I arch dam is evaluated completely, considering the yield zones, unbalanced force, plastic complementary energy norm, safety factors and other indexes. The reliability of design parameters is also verified by comparing the calculated results of inversion parameters and design parameters. The results show that K1 (the safety factor when crack initiating) of Jinping–I arch dam is double overload while K3 (the safety factor for ultimate load) is 8 times overload. Hence, it is confirmed that Jinping–I arch dam has a higher ultimate bearing capacity than other arch dams in 300 m height and thus the whole stability is guaranteed.