毛竹和棕麻加筋土的力学特性及工作机理分析

发布时间：2018-12-27 19:03

【摘要】：加筋土研究主要集中于筋材革新及加筋机理,目前,工程中常用的筋材多为土工格栅、土工布等人造加筋材料或者高分子聚合材料,较少采用天然加筋材料。若工程中能够就地取材,应用天然材料进行加筋,将具有良好的经济效益和生态效益。本文主要选用毛竹条和棕麻纤维这两种常见的天然加筋材料来研究其加筋土的力学特性及工作机理,主要包含以下几个内容:(1)通过室内拉伸试验研究毛竹条和棕麻纤维的抗拉性能,确定材料的物理力学性质,试验结果表明毛竹条和棕麻纤维均为柔性材料,且具有较强的抗拉强度,在拉坏前应力-应变呈现近似线性关系,可将毛竹条和棕麻纤维作为一种弹性加筋材料。(2)通过室内三轴试验和直剪试验研究毛竹条和棕麻纤维加筋砂和加筋黏土的力学性质,分析毛竹条和棕麻纤维加筋的工作机理,结果表明毛竹条和棕麻纤维加筋效果显著,且加筋土强度的增强主要体现在黏聚力的增加,符合摩擦加筋机理。毛竹条和棕麻纤维加筋存在最佳加筋尺寸和加筋率,本文通过试验测试确定了毛竹条加筋砂及棕麻纤维加筋砂和黏土的最优加筋率和加筋尺寸。(3)通过室内三轴试验对比了单一天然材料加筋和多种天然材料混合加筋效果,结果表明毛竹条和棕麻纤维混合加筋效果要优于毛竹条和棕麻纤维单独加筋,多种材料的适当混合加筋能更有效的发挥各筋材的加筋作用。(4)在试验结果基础上,建立了毛竹条和棕麻纤维加筋计算模型,得到加筋土中毛竹条“月牙”产生的“月牙约束力”及棕麻纤维加筋土应力应变增量的表达式。通过分析毛竹条和棕麻纤维混合加筋时的受力情况,得到毛竹条和棕麻纤维加筋的工作机理。
[Abstract]:The research on reinforced soil is mainly focused on the innovation and mechanism of reinforcement. At present, most of the reinforcement materials used in engineering are geogrid, geotextile, artificial reinforced materials or polymer polymeric materials, and less natural reinforced materials are used. If the local materials can be used and the natural materials can be reinforced in the engineering, it will have good economic and ecological benefits. In this paper, two common natural reinforced materials, bamboo strips and brown hemp fibers, were selected to study the mechanical properties and working mechanism of reinforced soil. The main contents are as follows: (1) the tensile properties of bamboo strips and brown hemp fibers were studied by tensile test, and the physical and mechanical properties of the materials were determined. The results showed that both bamboo strips and brown hemp fibers were flexible materials. Moreover, it has strong tensile strength, and the stress-strain relationship is approximately linear before tensile failure. Bamboo strips and brown hemp fibers can be used as an elastic reinforcement material. (2) the mechanical properties of reinforced sand and clay of bamboo strips and brown hemp fibers are studied by triaxial and direct shear tests. The working mechanism of reinforcing bamboo strips and brown hemp fibers was analyzed. The results showed that the reinforcement effect of bamboo strips and brown hemp fibers was remarkable, and the strength of reinforced soil was mainly reflected in the increase of cohesive force, which was in line with the mechanism of friction reinforcement. The optimum reinforcement size and reinforcement rate are found in bamboo strips and brown hemp fibers. In this paper, the optimum reinforcement rate and size of bamboo bar reinforced sand and brown flax fiber reinforced sand and clay are determined by test. (3) the reinforcement effect of single natural material and mixed natural material is compared by indoor triaxial test. The results showed that the effect of mixed reinforcement of bamboo strips and brown hemp fibers was better than that of bamboo strips and brown hemp fibers alone, and the proper reinforcement of various materials could play a more effective role in reinforcing each reinforcing material. (4) on the basis of the experimental results, A calculation model for reinforcing bamboo strips and brown hemp fibers was established, and the expressions of "crescent binding force" and stress-strain increment of bamboo strips reinforced with brown hemp fiber in reinforced soil were obtained. The working mechanism of the reinforcement of bamboo strips and brown hemp fibers was obtained by analyzing the stress of bamboo strips and brown hemp fibers.
【学位授予单位】：湖北工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU44

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