高拱坝相继从设计施工期进入蓄水运行期，超高水头蓄水导致孔隙水压力上升诱发了近坝库岸边坡的不可逆时效塑性变形，以往的工程设计很少考虑近坝岸坡与坝体之间的互馈作用，这给高拱坝的长期安全评价带来了难题。本文围绕蓄水期近坝库岸的变形现象和高拱坝的安全问题，通过典型案例分析、蠕变模型研究和数值计算模拟，研究蓄水导致的库岸变形机制，同时对长期蓄水条件下的拱坝安全度和加固措施效果进行评价。主要研究内容和成果如下：（1）整理总结了国内外典型拱坝工程近坝库岸的变形规律与机制，提出了三种变形模式：构造型、稳定岸坡型和亚稳定岸坡型；指出坝址区地质条件是内因，孔隙水压力上升是外因，两者共同作用导致了蓄水期近坝库岸的不可逆时效塑性变形；稳定岸坡型在高拱坝工程中更具一般性。探讨了库岸变形与水库诱发地震在规律和机理上的相关性，指出两者是同一力学机制作用下的不同表现形式。（2）针对稳定岸坡型的连续浅微变形特征，基于孔隙弹-黏塑性理论，建立了考虑水影响的蠕变模型，指出弹性、黏塑性和损伤本构使用不同的有效应力系数，分别影响蠕变过程的不同阶段。开展了考虑孔隙水压的蠕变试验，指出孔隙水压使稳态蠕变速率增大、加速蠕变阶段提前；基于试验结果对本构方程参数进行了拟合。（3）研发了基于考虑水影响的蠕变模型的孔隙黏弹性计算程序CPV-E和孔隙黏塑性计算程序CPV-P。通过单轴压缩和边坡算例验证了程序的有效性，并应用于锦屏一级左岸高边坡变形分析，指出水的力学作用主要体现在蓄水后的3~5年内，此期间为蓄水后拱坝-地基系统的变形调整期，初步证明了计算程序的可应用性。（4）分析了白鹤滩蓄水初期近坝库岸的变形规律，指出其为库水位上升导致的时效塑性变形，属于稳定岸坡型变形模式。基于考虑水影响的蠕变模型进一步分析了近坝库岸变形对于白鹤滩拱坝的影响，指出近坝库岸变形对拱坝的影响体现在建基面变形的不均匀不对称性和坝体局部应力集中上，加固措施效果体现在拱坝-地基系统整体性的增强和不对称性的改善。（5）研究了非线性安全度的确定方法及其在长期蓄水条件下的折减效应。基于模型试验和数值计算的对比分析，指出非线性安全度是评价拱坝整体稳定的控制性指标，提出了它的数值确定方法。将蓄水的长期作用概化为考虑有效应力和材料弱化的Drucker-Prager准则，给出东庄拱坝非线性安全度的折减系数为95%。
High arch dams have entered the impoundment operation period from the design and construction period one after another. The rising pore water pressure caused by ultra-high head impoundment will induce the irreversible aging plastic deformation of reservoir bank near dam. The mutual feedback between the reservoir bank near dam and the arch dam is rarely considered in the past design of high dams, which brings difficulties to the long-term safety evaluation of high arch dams. Focusing on the deformation phenomenon of reservoir bank near dam and the safety issue of high arch dam during impoundment, the deformation mechanism of reservoir bank caused by impoundment is studied through typical case analysis, creep model research and numerical simulation. At the same time, the safety degree of arch dam and the effect of reinforcement measures under the condition of long-term impoundment are also evaluated in this paper. The main research work and achievements are as follows:(1) The deformation law and mechanism of reservoir bank near dam of typical arch dam projects at home and abroad are analyzed, and three deformation modes are put forward: structural mode, stable bank slope mode and metastable bank slope mode. It is pointed out that the geological conditions in the dam site are the internal cause and the increased pore water pressure is the external cause, which together lead to the irreversible aging plastic deformation of the reservoir bank slope during impoundment period. The results show that stable bank slope is more common in high arch dam engineering. The correlation between reservoir bank deformation and reservoir-induced earthquakes in law and mechanism is discussed, and it is pointed out that they are different manifestations under the same mechanical mechanism.(2) Aiming at the continuous shallow deformation characteristics of stable bank slope mode, a creep model considering the influence of water is established based on the pore elastic-viscoplasticity theory, and it is pointed out that elasticity, viscoplasticity and damage constitutive model should use different effective stress coefficients to influence different stages of creep process respectively. The laboratory creep test considering pore water pressure is carried out, and it is pointed out that pore water pressure increases the steady creep rate and advances the accelerated creep stage. Based on the experimental results, the parameters of the constitutive equation are fitted.(3) Based on the creep model considering the influence of water, the program CPV-E and CPV-P are developed. The validity of the program is verified by uniaxial compression and slope examples, then it is applied to the deformation analysis of the high left bank slope of Jinping No.1 arch dam. It is pointed out that the mechanical action of water is mainly reflected in the 3~5 years after impoundment, which is the deformation adjustment period of arch dam-foundation system. The applicability of the calculation program is preliminarily proved.(4) The deformation law of Baihetan reservoir bank near dam in the initial impoundment period is analyzed. It is pointed out that it is the aging plastic deformation caused by the rise of reservoir water level and belongs to the stable bank slope deformation mode. Based on the creep model considering the influence of water, the influence of the deformation of reservoir bank near dam bank on Baihetan arch dam is further analyzed. It is pointed out that the influence of deformation of reservoir bank near dam on arch dam is reflected in uneven and asymmetric deformation of foundation surface and local stress concentration of dam body, and the effect of reinforcement measures is reflected in the enhancement of the integrity and improvement of asymmetry of arch dam-foundation system.(5) The determination method of nonlinear safety degree and its reduction effect under long-term impoundment condition are studied. Based on the comparative analysis of model test and numerical calculation, it is pointed out that the nonlinear safety degree is a control index to evaluate the overall stability of arch dam, and its numerical determination method is proposed. The long-term effect of impoundment is generalized into Drucker-Prager criterion considering effective stress and material weakening, and the reduction coefficient of nonlinear safety of Dongzhuang arch dam is given as 95%.
