加筋土结构的力学性状研究
发布时间：2018-09-19 12:31
【摘要】：本论文依托于国家自然科学基金项目:“格栅蠕变时砂卵石填料长期工作机理研究”,对加筋土结构的力学性状进行了研究。加筋土结构在港口码头、道路工程、地下工程、边坡工程等中的应用的广泛性,近年来,发现加筋土结构在长期荷载作用下加筋体中的筋材产生的蠕变松弛对加筋土的强度和稳定性有影响,所以有必要对加筋土结构的力学性状进行研究。本文的研究主要有以下几个方面:第一方面,利用剪力滞后理论的计算方法对加筋土结构进行受力分析,力学建模,研究得到各层筋材的应变和位移。计算结果表明各层筋材的应变值都是沿着筋材长度方向波动,各层筋材上应变最大值并不是发生在筋材与挡墙接触处,各层筋材的应变最大值发生在接触处和筋材一半之间的某个位置。第二方面,通过室内的拉拔试验,首先得到了筋材的应变并结合流变体的粘弹性蠕变模型研究了筋材在考虑应力水平下的蠕变情况。其次由于土体各向异性的存在,而现在的加筋土数值模拟大多数没有考虑到土体的各向异性,所以利用多次回填多次测试取应力应变均值的办法来考虑土体各向异性对筋材应力应变的影响。第三方面,本文在考虑筋材与填料在似摩擦作用下,得到了加筋土的主动区的计算方法,与规范采用的0.3H的方法进行对比。分析了主动区跟似摩擦系数、挡墙墙高、筋材间距等因素对主动区的影响,研究表明加筋间距对主动区的扩展影响最大。第四方面,首先利用水平层分析法解析了加筋土墙背土压力,得到了加筋土墙背土压力与墙高的函数关系,并与文献的实测资料进行了对比验证。其次分析了填料的内摩擦角,挡墙墙高,摩擦系数等因素对加筋土墙背土压力的影响。再利用试验得到的土工格栅的本构关系,建立加筋土中各层筋材的应变预测方法,用此预测方法可以估计加筋土中筋材的寿命。最后分析了筋土之间的似摩擦系数、挡墙墙高等因素对应变预测的影响。
[Abstract]:Based on the project of National Natural Science Foundation of China: "Study on long-term working mechanism of sand-gravel filling during grid creep", this paper studies the mechanical properties of reinforced soil structure. It is necessary to study the mechanical properties of reinforced soil structures because creep relaxation of reinforcement materials in reinforced bodies under load has an effect on the strength and stability of reinforced soil. The results show that the maximum strain of each layer is not at the contact point between the reinforcement and the retaining wall, and the maximum strain of each layer occurs somewhere between the contact point and the half of the reinforcement. In this paper, the strain of reinforcement is obtained by pull-out test in laboratory, and the creep behavior of reinforcement under stress level is studied by viscoelastic creep model of rheological body. The influence of soil anisotropy on the stress and strain of reinforcement material is considered by means of the mean value of stress and strain measured many times. Thirdly, the calculation method of active zone of reinforced soil is obtained by considering the effect of similar friction between reinforcement material and filler, and is compared with the 0.3H method adopted in the code. The research shows that the reinforcement spacing has the greatest influence on the expansion of the active zone. Fourthly, the horizontal layer analysis method is used to analyze the earth pressure behind the reinforced earth wall, and the functional relationship between the earth pressure behind the reinforced earth wall and the wall height is obtained. The influence of the internal friction angle of the filler, the height of the retaining wall and the friction coefficient on the back earth pressure of the reinforced earth wall is analyzed. Then the strain prediction method of the reinforcement in each layer of the reinforced earth is established by using the constitutive relation of the geogrid obtained from the test. The life of the reinforcement in the reinforced earth can be estimated by this prediction method. Friction coefficient and retaining wall high factor correspond to the influence of variable prediction.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU43
本文编号：2250126
[Abstract]:Based on the project of National Natural Science Foundation of China: "Study on long-term working mechanism of sand-gravel filling during grid creep", this paper studies the mechanical properties of reinforced soil structure. It is necessary to study the mechanical properties of reinforced soil structures because creep relaxation of reinforcement materials in reinforced bodies under load has an effect on the strength and stability of reinforced soil. The results show that the maximum strain of each layer is not at the contact point between the reinforcement and the retaining wall, and the maximum strain of each layer occurs somewhere between the contact point and the half of the reinforcement. In this paper, the strain of reinforcement is obtained by pull-out test in laboratory, and the creep behavior of reinforcement under stress level is studied by viscoelastic creep model of rheological body. The influence of soil anisotropy on the stress and strain of reinforcement material is considered by means of the mean value of stress and strain measured many times. Thirdly, the calculation method of active zone of reinforced soil is obtained by considering the effect of similar friction between reinforcement material and filler, and is compared with the 0.3H method adopted in the code. The research shows that the reinforcement spacing has the greatest influence on the expansion of the active zone. Fourthly, the horizontal layer analysis method is used to analyze the earth pressure behind the reinforced earth wall, and the functional relationship between the earth pressure behind the reinforced earth wall and the wall height is obtained. The influence of the internal friction angle of the filler, the height of the retaining wall and the friction coefficient on the back earth pressure of the reinforced earth wall is analyzed. Then the strain prediction method of the reinforcement in each layer of the reinforced earth is established by using the constitutive relation of the geogrid obtained from the test. The life of the reinforcement in the reinforced earth can be estimated by this prediction method. Friction coefficient and retaining wall high factor correspond to the influence of variable prediction.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU43
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