【作者】 李永新；

【导师】 何蕴龙；

【作者基本信息】 武汉大学 ， 水工结构工程， 2005， 硕士

【摘要】 碾压混凝土坝和面板堆石坝是当今坝工界的两种主要坝型,两种坝型都反映了筑坝技术在筑坝材料、结构设计及施工工艺等方面相互影响和相互促进的规律。胶结砂砾石坝是综合面板堆石坝和碾压混凝土坝在筑坝材料、结构设计及施工工艺等方面的优势而产生并发展起来的一种新坝型。 对于一种新型坝而言,其强度问题和稳定问题是非常关心的问题。本文应用强度折减有限元方法对胶结砂砾石坝的强度问题和稳定问题进行了探讨。 胶结砂砾石筑坝技术的核心是将经过简单筛分的天然砂砾石料加入适量的水泥和水搅拌,并直接用于筑坝。其带来的显著效果是可大幅度降低成本、高效快速施工、修筑高安全性大坝。 从本质上讲,胶结砂砾石材料是一种碾压材料,存在结构弱面和施工弱面。胶结砂砾石材料的性能介于碾压混凝土材料和土石材料之间,并受水泥用量、水用量、骨料级配、施工层面处理等因素影响。 胶结砂砾石坝的安全评价包括应力强度和抗滑稳定两个方面。通过降低强度指标或者增加荷载,利用弹塑性有限元研究坝体的破坏过程并评价大坝的安全,可将坝的应力强度和抗滑稳定的安全评价合二为一。胶结砂砾石坝的应力与稳定是大坝安全和经济的控制性因素,同时也是保障大坝防渗体系正常工作的前提。 针对胶结砂砾石材料的弱面特性,本文运用变形等效原理,推导了含弱面的块体等效有限元计算公式。从结果来看,块体等效计算公式是比较合理和合适的。 针对胶结砂砾石坝的结构特性,本文探讨了适合于胶结砂砾石坝应力与稳定有限元分析的坝基范围和坝基边界约束条件。研究表明,坝基在上下游和深度三个方向取2.5倍坝高且坝基边界铰接约束时,坝基边界条件是比较合理和合适的。 胶结砂砾石材料性能是影响胶结砂砾石坝应力与稳定的重要材料因素。本文分别探讨了胶结砂砾石本体材料的粘聚力c、内摩擦角γ、杨氏模量E和胶结砂砾石层面材料的粘聚力c、内摩擦角γ、杨氏模量E对胶结砂砾石坝应力与稳定的影响的敏感性。研究表明,胶结砂砾石材料的增强可以提高胶结砂砾石坝的应力与稳定;胶结砂砾石材料性能参数对胶结砂砾石坝应力与稳定影响的敏感性是各不不同的。 坝基杨氏模量E也是影响胶结砂砾石坝应力与稳定的重要材料因素。本文分别探更多还原

【Abstract】 It is two kinds of main dam types of the dam engineering to roller compacted concrete dam and concrete faced rockfill dam nowadays. Both of them reflected the pattern of influencing each other and mutual promotion in dam material, structural design and construction method of dam construction technique. As a new kind of dam type, cemented sand & gravel dam has produced and developed ,which integrated excellences of dam material、 structural design and construction method of roller compacted concrete dam and concrete faced rockfill dam.As to a new kind of dam type, its intensity & stability is the first and important issue. This thises study the intensity & stability of cemented sand & gravel dam by adoption strength reduction coefficient method and ansys parameter design language.The key technique of cemented sand & gravel dam is to mix appropriate amount water, appropriate amount cement and natural sand & gravel material ,then to use building a dam directly, build up a high security dam.From the essential general, as roll compacted concrete, sand & gravel material is rolled material,which has structure and constructing weak layer. The properity of cemented sand & gravel is between roller compacted concrete and earth and rock material,and it is influenced by many factors easily,such as cement content, water content, Aggregate gradation, layer treatment of construction and so on.The safety evaluation of cemented sand & gravel dam involving include two respects, stress intensity and stability against sliding. Through reducing intensity index or increasing load, it can study destructive process of dam body by applying elastic plasticity Finite element method , and it can assess security of dam body by integrating stress intensity and stability against sliding The stress & stability of Cemented sand & gravel dam is a controlling factor of the safety and economic.On the other hand,it is also a precondition to seepage prevention structure work normally.Contraposing the characteristic of weak layer of cemented sand & gravel material, the paper derive equivalently Calculate formulae for body including weak one, applying the Principle of Equivalent Deformation. According to result of calculation, its computing technology is suitable .Contraposing special structure of cemented sand & gravel ,this tractate study on condition of dam foundation.which suitable for finite element are analysis of stress & stability to cement sand & gravel dam . Studies have shown , the transformation of dam foundation influence analysis trivially when the bound of dam foundation is lengther than 2.5 times the high of cement sand & gravel dam.and the border knuckle joint of dam foundation is restrained.This peper study sensation of cohesion , friction angle and Young’s modulus of noumenonn material and aspect material. According to analysis result, as the accretion of intensity of cement sand & gravel material, it will augment the security of dam body . The impact on dam of the material parameter has nothing in common with each other.It is a important factor for modulus of elasticity of dam foundation to influence stress & stability analysis of cemented sand & gravel dam . This text study sensation of modulus of elasticity of homogeneous dam foundation and nohomogeneous dam foundation. According to analysis result, cement sand & gravel dam adapt to the weak dam foundation ; as the accretion of modulus of elasticity of dam foundation , it will augment the security of dam body; exert a tremendous influence to cement sand & gravel dam; Compare, the front part weaker dam foundation is more favorable.更多还原