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我国已建成的特高拱坝逐渐由设计施工期过渡到蓄水运行期,其试验及监测成果表明,开挖、蓄水等扰动将加快拱坝枢纽区山体边坡的流变变形,这些长期变形对拱坝安全构成严重威胁。提出岩质高边坡长期变形对拱坝安全的影响分析方法,采用黏弹–塑性流变本构模型,计算锦屏一级左岸边坡在运行期的长期变形。以此变形为基础,引入极限分析的思想,提出基于边界位移法和变刚度的强度折减法,对边坡变形对拱坝的影响进行分析评价。边界位移法是在模型边界解除约束,施加固定位移,模拟边坡长期变形;变刚度的强度折减法是基于弹塑性和流变模型之间的内在联系,同时降低刚度和强度,来模拟边坡变形对拱坝影响,具有完备的理论基础。对锦屏一级拱坝左岸高边坡的长期变形进行分析预测,评价了拱坝承受边坡长期变形的安全度。研究表明,左岸边坡长期变形在一定程度上对坝体有益,流变稳定时,坝体屈服区、塑性余能范数都有减小,应力状况得到改善;拱坝可承受6倍以上的边界位移超载。因此,应重点关注应力集中等建基面局部区域对拱坝长期稳定性的影响。
The construction of UHV arch dam in China has been gradually transition from design and construction period to impoundment operation. The test and monitoring results show that the excavation and storage disturbance will speed up the deformation of mountain slopes in the arch dam junction. These long-term The deformation poses a serious threat to the safety of the arch dam. A method of analyzing the influence of long-term deformation of rocky slope on the safety of arch dam is presented. The viscoelastic-plastic rheological constitutive model is used to calculate the long-term deformation of the slope of the left bank of Jinping during operation. Based on this deformation, the idea of limit analysis is introduced, and the strength reduction method based on boundary displacement method and variable stiffness is proposed to analyze and evaluate the influence of slope deformation on arch dam. Boundary displacement method is used to simulate the long-term deformation of the slope by releasing the constraint at the boundary of the model and simulating the long-term deformation of the slope. The strength reduction method of the variable stiffness is based on the intrinsic relation between elasto-plasticity and the rheological model while reducing the stiffness and strength to simulate the slope Deformation on the arch dam, with a complete theoretical basis. The long-term deformation of the left bank slope of Jinping-Ⅰ arch dam is analyzed and predicted, and the safety of the arch dam subjected to the long-term deformation of the slope is evaluated. The results show that the long-term deformation of the left bank slope is beneficial to the dam to some extent. When the rheology is stable, the yield area and plastic residual energy norm of the dam decrease, and the stress condition is improved. The arch dam can withstand more than 6 times Boundary displacement overload. Therefore, we should pay attention to the impact of stress concentration and other local areas on the long-term stability of arch dam.