风沙环境下混凝土受冲蚀损伤机理及评价研究

发布时间：2018-01-28 02:30

本文关键词： 风沙环境混凝土冲蚀磨损冲蚀机理评价方法　出处：《内蒙古工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着我国经济建设的发展,混凝土结构应用日益广泛,结构在恶劣环境(比如沙尘暴、严寒、霜冻、酸、碱和盐等)中遭受侵蚀或者腐蚀作用,使得结构耐久性降低,服役期限缩短,致使结构存在安全隐患,影响人们的正常使用。本文主要研究区域为内蒙古中西部沙漠地区,该地区公路和桥梁等混凝土设施长期受到沙尘暴自然灾害的影响,导致结构的耐久性和安全性降低,严重影响结构的使用寿命。本文在研究内蒙古中西部地区风沙环境的特点和混凝土物理、力学性能和冲蚀接触力学行为及其理论的基础上,采用气流挟沙喷射试验方法,研究了混凝土的冲蚀磨损量或冲蚀率在不同强度和不同风沙环境冲蚀参数下的关系,得出混凝土的冲蚀规律和冲蚀机理,结合混凝土和风沙环境特征,提出了一种混凝土的冲蚀磨损量评价方法,该方法可评价混凝土受冲蚀磨损的程度,使得试验结果更具有实际意义。具体内容如下:1.本文对内蒙古中西部地区的风沙气象环境进行了大量的研究,分析其特点后选择风沙冲蚀参数。结合内蒙古中西部的气候特点设计混凝土的抗冲蚀试验工况,设计了三组不同强度等级的混凝土,进行混凝土在不同强度和不同风沙环境冲蚀参数的对比试验研究。2.采用气流挟沙喷射法进行混凝土抗冲蚀性能的试验研究,对研究结果进行统计分析,结果表明:(1)同强度混凝土的冲蚀率在相同条件下随着风沙流冲蚀角度的增大而增大,90°时达到最大;(2)同强度混凝土的冲蚀率在相同条件下随着风沙流冲蚀速度的提高而增大,并且二者近似成指数关系;(3)同强度混凝土的冲蚀率在相同条件下随着下沙率的增大呈先增大后减小的趋势;(4)试验表明混凝土在冲蚀过程中没有明显的孕育期,但是有上升期和稳定期。通过SEM扫描电镜观察了冲蚀损伤部位表面形貌,其破坏机理表现为:在低冲蚀角下破坏机制表现为类似表面划伤破坏作用;在高冲蚀角下破坏机制表现为冲击压痕破碎作用。3.通过建立风沙流粒子冲蚀磨损力学模型,在建立的力学模型基础上进行风沙流作用下混凝土冲蚀磨损力学行为及其理论计算分析。4.本文提出了一种混凝土在风沙环境下抗冲蚀磨损程度的评价方法以及相应的评价公式,利用该评价计算公式分析了混凝土冲蚀磨损重量同冲蚀速度和冲蚀角度之间的关系,并把评价计算公式结果与试验结果进行了对比,证实了评价公式的可行性和可靠性。
[Abstract]:With the development of economy in China, the application of concrete structure is more and more widely, the structure in the harsh environment (such as sandstorm, cold, frost, acid, alkali and salt) in erosion or corrosion, the durability of the structure is reduced, the service period is shortened, resulting in structure safety hazards, affecting the normal use of the people. In this paper, the main research area for the western Inner Mongolia desert area, the area has long been the concrete facilities such as roads and bridges of sandstorm natural disasters, leading to the safety and durability of structure is reduced, seriously affect the structure of life. Based on the characteristics of the wind environment in central and western regions of Inner Mongolia and the physical and mechanical properties of concrete and foundation erosion mechanical behavior and contact theory, the sediment air injection test method, studied the concrete erosion or erosion rate in different intensity and The relationship between wind erosion parameters under the law, erosion and erosion mechanism of concrete is obtained, combining with the environmental characteristics of sand and concrete, put forward an evaluation method for the erosion wear of concrete, this method can evaluate the degree of erosion of concrete, the test result has more practical significance. The specific contents are as follows: 1. in the Midwest the sandstorm of Inner Mongolia meteorological environment made a lot of research and analysis of the characteristics of wind erosion parameters. After the selection of anti erosion test design of concrete combined with the climate characteristics of central and Western Inner Mongolia, the design of the three groups of different strength grade of concrete, the test of concrete in different intensity and different wind erosion parameters test by.2. sediment air injection method for concrete anti erosion performance, statistical analysis, the research results show that: (1) the same The erosion rate of concrete strength under the same conditions increase with the erosion angle of sand flow and 90 degrees maximum; (2) with the rate of erosion strength of concrete under the same conditions with the increase of erosion of sand flow rate increased, and the two approximate exponential relationship; (3) erosion with strength of concrete the rate under the same conditions with the increase of Xiasha rate decreased; (4) test showed that the concrete in erosion process has no obvious incubation period, but the rising phase and stable phase. The erosion damage parts of the surface morphology was observed by SEM scanning electron microscope, the failure mechanism is: in the low erosion angle of failure mechanism showed similar surface scratch damage; at high angle erosion damage mechanism for impact indentation crushing effect through the establishment of the.3. sand particle erosion mechanics model, based on the established mechanical model Based on the analysis of.4. this paper presents a concrete in sandy environment erosion degree evaluation method and the evaluation formula of sand flow under the action of concrete erosion mechanics behavior and theory, using the formula of the evaluation and analysis of the relationship between the concrete erosion weight with the erosion rate and erosion angle, and the evaluation the calculated results were compared with the experimental results, proved the feasibility and reliability evaluation formula.

【学位授予单位】：内蒙古工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU528

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