库水作用下云南库岸红土干湿循环特性研究

发布时间：2018-06-11 13:03

本文选题：库岸红土 + 库水侵蚀　；参考：《昆明理工大学》2015年硕士论文

【摘要】：近几年来云南省所遭遇的普遍高温干旱,以及雨季来临时的持续降雨,导致云南省境内红土型水库崩塌、病险加剧等相关问题日益加剧。文章以云南省昆明市红土型水库库岸边坡作为研究对象,提出开展“云南红土型库岸侵蚀过程研究”这一学术课题。且围绕这一主题,开展了红土型水库库岸边坡侵蚀模型试验与红土试样干湿循环特性试验。通过开展红土型库岸边坡的模型试验表明：库水位的升降变化导致位于库水位以下的红土土压力减小,红土中的孔隙水压力增大。同时,反复的库水位升降变化作用导致库岸边坡大颗粒土粒向库岸的上游坡脚处迁移,迁移变化导致红土的颗粒分布变化,颗粒级配有原来的级配良好变为级配不良；通过对红土开展反复的干湿循环特性试验研究表明：对红土进行增湿时,红土的抗剪强度首先迅速减小,之后会缓慢回升,随着增湿过程的继续进行,其强度最终完全丧失。对红土进行脱湿时,红土的抗剪强度会持续性的缓慢回升。反复的干湿循环作用会导致红土的抗剪强度减小。同时,反复的干湿循环作用会导致红土的压缩性能变大,导致红土的渗透性能增大；通过对红土开展微结构特性试验研究表明：较低倍数的放大效果可以从整体上掌握红土的孔隙及土体的松散与紧密程度。较高的放大倍数可以更为细观的观察到红土内部的孔隙及土颗粒分布状况,同时可以观察到红土内部的颗粒圆形度及颗粒复杂度等微结构特征参数。同时,随着浸泡时间的延长,红土内部的孔隙变大,红土颗粒表面也越来越不规整。对红土较高温度的养护作用会使得红土颗粒间产生比较低养护温度及常温养护作用更大的孔隙；反复的干湿循环过程中发生着红土与库水之间的物理、化学以及力学作用。其中,物理作用包括：软化、侵蚀、泥化等作用。化学作用包括：离子的交换吸附作用、同晶置换作用、红土矿物质的电离水解等作用过程；力学作用包括库水对红土抗剪强度、压缩特性以及渗透特性的影响。
[Abstract]:In recent years, the general high temperature and drought encountered in Yunnan Province, as well as the continuous rainfall during the rainy season, have led to the collapse of lateritic reservoirs in Yunnan Province and the worsening of disease risk and other related problems. Taking the bank slope of lateritic reservoir in Kunming, Yunnan Province as the research object, this paper puts forward the academic subject of "study on the erosion process of Yunnan lateritic reservoir bank". According to this theme, model tests of slope erosion and dry and wet cycle tests of laterite samples were carried out. The model test of lateritic reservoir bank slope shows that the fluctuation of reservoir water level results in the decrease of laterite pressure and the increase of pore water pressure in laterite. At the same time, the repeated changes of reservoir water level lead to the migration of large granular soil particles from the bank slope to the upstream slope foot of the reservoir bank, and the migration change leads to the change of the particle distribution of the laterite, and the grain grade with the original good gradation is changed into bad gradation. The results of repeated dry-wet cycle tests show that the shear strength of laterite decreases rapidly at first and then rises slowly. With the humidification process, the strength of red soil is completely lost. When dehumidifying the red soil, the shear strength of the red soil will increase slowly and continuously. Repeated dry and wet cycling will reduce the shear strength of red soil. At the same time, repeated dry-wet cycle will lead to the compression performance of red soil become larger, resulting in the increase of the permeability of red soil; The microstructural characteristics of laterite are studied. The results show that the porosity of laterite and the looseness and compactness of soil can be grasped by the magnifying effect of lower multiple. At higher magnification, the pore and particle distribution in red soil can be observed more meso-scopically, and the microstructural characteristic parameters such as roundness and complexity of particles in laterite can be observed at the same time. At the same time, with the prolongation of soaking time, the internal pores of laterite become larger, and the surface of laterite particles becomes more and more irregular. The curing effect on the higher temperature of laterite will result in larger porosity between the particles of red soil than at low curing temperature and curing at normal temperature, and the physical, chemical and mechanical action between laterite and reservoir water will occur during repeated dry-wet cycle. Among them, physical action includes: softening, erosion, mud and so on. The chemical action includes ion exchange adsorption, isomorphic displacement, ionization and hydrolysis of laterite minerals, and the effects of reservoir water on shear strength, compression and permeability of laterite.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P642.132

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