【作者】 阿里木·吐尔逊；

【导师】 徐卫亚； 阮怀宁；

【作者基本信息】 河海大学 ， 岩土工程， 2005， 博士

【摘要】 大坝的老化是国内外许多大坝出现各类病态问题甚至发生事故的主要原因之一,但从系统性和深度等方面大坝老化研究主要集中在上部混凝土及金属结构的老化研究上,而由于坝基本身组成与结构以及所处环境的复杂性,缺少老化过程的系统研究,尤其是定量研究相当薄弱,还不足于满足全面评价坝基长期稳定性的需要。本文围绕数值化地模拟坝基老化过程这个主题进行了深入的研究,其所做的主要工作如下: 1.通过国内外众多大坝出现的各类病态问题和事故的归纳,按照从问题到本质、从现象到实质的思维方法,总结出了坝基老化的概念及其实质,从不同角度强调了坝基老化研究的必要性和意义,阐述了坝基老化研究的现状、存在的问题以及趋势,并以大坝修建后应力环境、水环境以及化学环境变化所引起的物理机械作用和岩—水化学作用对坝基岩土体物理化学特性影响的时效性为出发点提出了坝基老化研究的范围、目的和基本思路。 2.从水文地球化学的观点出发,对坝基老化的具体工程表现即所引起的各类工程问题进行了详细的分类和论述;深入探讨了坝基老化的岩—水化学作用过程及其影响因素;提出了坝基岩—水系中化学反应的平衡热力学和化学动力学两种定式化方法,并讨论了它们各自的优点、局限性和应用平衡热力学定式化方法所要满足的局部平衡条件;建立了坝基老化岩—水—化学作用数值模拟方法体系,并详细阐明了其中反向模拟、正向模拟和岩—水—化学耦合模拟三种方法的基本思想、原理、优点和局限性、适用条件和范围等。 3.按照从结果到原因的反向思维方式,利用随机误差最小原理、质量守恒原理和电中性原理建立了反向坝基老化模型,利用L1优化问题的Barrodale—Roberts算法对模型进行了求解,并将模型应用到新安江大坝右坝段坝基老化数值模拟分析当中取得了满意的结果。 4.利用质量作用原理、质量守恒原理和电中性原理建立了正向坝基老化模型,联合利用Newton—Raphson法和Barrodale—Roberts算法对模型进行了求解,并通过模型在坝基帷幕老化的温度依赖性以及三峡大坝坝基老化数值模拟分析中的成功应用验证了它的实用性和可靠性。 5.根据渗流、溶质迁移以及岩—水间地球化学反应三个过程在坝基老化中的实际耦合模式,建立了坝基老化的岩—水—化学耦合模型,联合利用有限体积差分法、线性方程组的迭代算法、Newton—Raphson法和Barrodale—Roberts更多还原

【Abstract】 Dam ageing is one of the main causes of various abnormal problems and even accidents occurred in many dams. Presently, the research on dam ageing is mainly focused on the ageing of dam concrete and metal structures, however there is a lock of systematic research, especially quantitative research, on dam foundation ageing. Due to this reason, aiming at the numerical simulation of dam foundation ageing, the following studies are carried out in this paper:1. Through generalizing various abnormal problems and accidents occurred in dams, the concept and nature of dam foundation ageing are summarized; From the point of different aspects, the necessity and significance of systematic research on dam foundation ageing are emphasized; The present status, existing questions and trends of dam foundation ageing research are set forth; The scope, aim and study line of dam foundation ageing research are brought forward, according to the effect of mechanical and chemical processes (which are arose from the stress, water and chemical environment changing after construction of the dam) to the dam foundation material properties.2. From the point of hydro-geochemistry, various adverse engineering problems arose from dam foundation ageing are detailedly classified and profoundly discussed; The hydro-geochemical process of dam foundation ageing are clarified; Equilibrium and kinetic formulation methods of chemical reactions in the dam foundation water-rock interaction system are put forward, and their advantages, disadvantages and the Local Equilibrium Condition required for the equilibrium formulation are discussed; The numeric Hydro-Geo-Chemical modeling system of dam foundation ageing are established, and main ideas, principles, advantages, disadvantages and applicability of Inverse, forward and coupled hydro-geo-chemical models in the system are discussed in detail.3. The inverse model for dam foundation ageing is established by using mole balance and charge balance equations; By using Barrodale—Roberts algorithm, numerical solution to the model is performed; Applying the model to the ageing status analyses of Xin an Jiang Dam foundation, satisfactory results are obtained.4. The forward model for dam foundation ageing is established by using mass action, mole balance and charge balance equations; By the incorporated using of Newton—Raphson and Barrodale—Roberts algorithms, numericalsolution to the model is performed; Applying the model to the temperature dependency analyses of grout curtain ageing and status analyses of Three Gorges Dam foundation ageing, practicability and reliability of it are certified.5. Based on the real interaction modes between flow, transport and water-rock chemical reactions in the dam foundation ageing process, the coupled hydro-geo-chemical model for dam foundation ageing is established; Numerical solution to the model is performed by incorporated using of Finite Volume Difference method, iterative algorithm for linear equations, Newton — Raphson algorithm and Barrodale—Roberts algorithm; Applying the model to the 2-dimensional ageing analyze of a dam foundation, the ultimate target of comprehensive characterizing of dam foundation ageing process in space and time is achieved.更多还原