红土坝基水工特性劣化研究

【作者】 陈锐；

【导师】 杨华舒；

【作者基本信息】 昆明理工大学 ， 水利水电工程， 2010， 硕士

【摘要】 本课题侧重于对红土坝基在水工条件下的劣化过程以及坝基发生深层渗漏进行研究,提出坝基材料在水工环境下的劣化机理,为土石坝的坝址选择、防渗技术、除险加固措施等提供理论参考。基于红土形成的新理论,在研究过程中归纳总结了碳酸盐岩上覆红土的各种特征；分析了云南山区河流、湖泊的酸碱特性；深入探讨了红土颗粒间胶结物的组成成分、坝基红土与库水发生的水土化学作用后的劣化过程、以及库水与上覆红土共同作用对碳酸盐岩表层岩性的改变。提出了红土坝基在库水环境下的演变过程,坝基红土与库水的水化学作用对其下伏的碳酸盐岩的腐蚀离析机理,解释了坝基渗流劣化的根本原因和发展趋势。论文主要分为以下几个部分：(1)归纳总结碳酸盐岩上覆红土的形成过程以及形成模式；红土的宏观结构、细观结构、微观结构；水土作用的机理、水土作用的力学效应及其地下水变异后对土体的影响。(2)探讨了碳酸盐岩上覆红土的构造、各土层的特征、化学成分,以及云南红土的各项物理力学指标。(3)通过现场实验,分析了云南山区河流、水库的水质,得出云南水质的酸碱特性。(4)研究了红土颗粒间的胶结物的矿物组成及化学成分,胶结作用对土体结构稳定的重要性。(5)深入分析了坝基红土在库水环境中发生的水土相互作用：坝基处于高压环境,在此区域存在着库水压力、坝体自重、坝基扬压力、渗透压力等,水在各种压力的作用下,渗入坝基红土孔隙中,将土颗粒间的胶结物溶蚀并带走,破坏了原有的平衡状态。坝基红土与库水发生化学作用,导致粘粒不断减少,粒间连结力、结构强度降低；坝基红土中土颗粒间距逐渐增大,土颗粒被架空；进而使坝基土体的压缩系数和透水性增大,抗剪力、内摩擦角、内聚力降低。水土相互作用是一个长期积累的过程,坝基红土经过长期溶蚀作用不断向粉质粘土、沙土方向劣化。本文的研究成果可为水利水电工程的建设、土石坝水库大坝的管理和防渗加固技术提供切合实际的适用性评价和改进方案指导,并为采用其它主材的土石堤坝渗流研究、对堤坝防渗技术的发展完善提供参考。更多还原

【Abstract】 The research put emphases on the dam foundation of laterite deteriorated process under hydraulic project condition and has in-depth on the base of dam., proposed deteriorates the mechanism of dam foundation material in the hydraulic environment, provide theoretical reference to dam site choice, anti-seepage technology and eliminates the dangerous reinforcement measure of earth-rock dam.The formation of a new theory based on clay, summarized in various features of clay overlying carbonate; analysed acid-base characteristics of mountain rivers, lakes in Yunnan province; depth of the composition of clay particles of cement, the degradation process of dam foundation and reservoir water occurred in clay soil and water chemistry, library of water and clay overlying the common role of the carbonate rock surface changes. Raised the evolution of red clay dam foundation in the library environment, dam foundation red soil and the reservoir water chemistry of carbonate rocks of its underlying segregation mechanism of the corrosion, explains the deterioration of the root causes of the dam foundation seepage and development trend.Thesis is divided into the following sections:(1) Summarized carbonate rocks overlying the clay model of the formation process and the formation, the macro-structure, micro-structure, micro-structure of laterite, the mechanism of water-soil interaction, the mechanical effect of water-soil interaction and variation of groundwater after the impact of soil. (2) Discusses the carbonate rocks overlying the red clay structure, the characteristics of the soil, chemical composition and the physical and mechanical properties of Yunnan red clay. (3) Through on-site test analysis of mountain rivers, reservoirs, water quality and arrive at the water quality of acid-base characteristics of Yunnan. (4) Studied the clay particles of the cement mineral composition and chemical composition, Cementation of the importance of structural stability of soil. (5) In-depth analysis of soil and water interactions under library of water environment, reservoir water pressure, dam weight, dam foundation uplift pressure, osmotic pressure and so on in the foundation of dam, under the effect of various pressures, water penetrate pores clay dam foundation, between the soil particles, and removed the cement dissolution, destroyed the original state of equilibrium. Lead shrinking clay, links between grains force and structural strength to reduce, soil particle spacing is gradually increasing and become a mere figurehead, so dam foundation soil compression coefficient and permeability increased, shear force, internal friction angle, cohesion to reduce. Soil and water interaction is a long-term accumulation process. Dam foundation on clay develop to silty clay, sand direction of deterioration after a long dissolution.This research not only providing practical applicability of evaluating and improving program guidance of hydropower projects, the management of earth-rock dam and impervious reinforcement technique,but also to use other primary materials of the earth and rock dam seepage study on the development and improvement of dam seepage control technology to provide reference.更多还原