论文标题:麦秸秆加筋固化滨海盐渍土的筋材防腐与力学特性研究
Study on Anti-corrosion and Mechanical Characteristics of Wheat Straw Using for Reinforced Saline Soil in Inshore
论文作者
论文导师 柴寿喜,论文学位 硕士,论文专业 岩土工程
论文单位 天津城市建设学院,点击次数 28,论文页数 82页File Size5927K
论文网 http://www.lw23.com/lunwen_284242487/
anticorrosive wheat straw;; reinforced soil;; saline soil in inshore;; SH agent;; tension;; elongation;; microstructure
滨海地区的地基土为软土,表层广泛分布的滨海盐渍土具有盐胀、溶陷、腐蚀和吸湿软化问题,未经固化或加固处理不能满足填筑高等级公路路堤的强度和变形要求。土的改性加固可分为压密固结、加筋加固、固土剂胶结等方式,加筋加固是其中一个主要方面。以防腐处理后的麦秸秆作加筋材料固化滨海盐渍土,可提高滨海盐渍土的强度、增强土体的整体性和稳定性,丰富加筋土强度理论。开发麦秸秆加筋土新技术,对岩土工程加固技术的创新具有重要意义,为滨海盐渍土地区的高等级公路路堤的工程建设提供理论支持和技术指导。 加筋土的强度和稳定性主要是依靠填土自重和筋土之间的摩阻力来实现的,因此只有研究麦秸秆自身的力学特性,才能进一步研究麦秸秆加筋土的强度增长规律。论文的主要研究内容及成果如下: (1)测试了天然麦秸秆和浸胶麦秸秆的吸水率。麦秸秆的结构决定其具有较强的吸水性,易受到微生物的侵蚀而导致腐烂。将麦秸秆浸泡在SH胶中一段时间后,麦秸秆内部孔隙中渗入了胶液,内外表皮上附着了胶膜,可有效隔断或减弱麦秸秆与水的接触。结果表明,浸胶使麦秸秆的抗水性能得到较大的提高。 (2)完成了1000余组无骨节和1骨节麦秸秆,在天然、浸水、浸胶、以及浸胶后再浸水4种工况下的拉力和延伸率测试,以此研究麦秸秆的力学特性。结果表明,无骨节麦秸秆的拉力和延伸率都高于1骨节麦秸秆;SH胶附着在麦秸秆内外表皮上,且渗入到麦秸秆内部,提高了麦秸秆的拉力和延伸率。 (3)完成了浸胶前、浸胶后麦秸秆的微结构观测,并利用Leica QWin5000图形处理软件对SEM照片进行处理和分析。分析结果表明,浸水麦秸秆的孔隙面积大于天然麦秸秆;浸胶使麦秸秆的孔隙面积减小,减少的孔隙面积完全被SH胶填充。 (4)利用一元回归分析法研究了浸胶麦秸秆的力学指标与微结构参数的相关性。分析结果表明,浸胶麦秸秆的拉力和延伸率与平面孔隙率密切相关,并解释了宏观力学指标变化的微观机理。 (5)为进一步研究麦秸秆加筋土的强度增长规律,提出了麦秸秆加筋固化滨海盐渍土的试验方案构想。
Foundation soil in inshore region is soft soil. Saline soil has the problem of dilatation, collapsibility, corrosive and water absorbing quality, which covered on the surface of foundation soil in inshore. To satisfy the requirement of strength and deformation of road embankment of highway, Saline soil in inshore should be solidified in the stage of construction. The solidified methods of soil include stabilization by compaction, reinforcement, and chemical stabilization, and the reinforcement is a major means. Saline soil in inshore is reinforced with anticorrosive wheat straw, which can increase the strength, integral quality and stability of saline soil. It could supplement the theory of reinforced soil also. It is significant for the innovation of geotechnical solidified technology that reinforced soil with wheat straw is studied. The technology of reinforced soil with wheat provides guidance on the theory and technology of road embankment of highway. It has been proved that the strength and stability of reinforced soil mostly depended on the weight of filling soil and the friction between reinforced material and soil. For discussing the increasing rule of strength of reinforced soil with wheat straw, the mechanical characteristic of wheat straw should be studied. Main research contents and results are as follows: (1) Tested the water absorbing ratio of original wheat straw and wheat straw marinated in SH agent. Wheat straw has strong absorbing water quality because of its special structure, and has been corrupted by microbe. It has been proved that wheat straw marinated in SH agent for some time was infiltrated SH agent in the pores of wheat straw, and SH agent was adhered to its surface. The results show that the SH agent enhanced the water- resistant of wheat straw. (2) For studying the mechanical characteristics of wheat straw, the tests of tension and elongation of 1000 wheat straws with 1 condyle and without condyle were carried out. These wheat straws included original, marinated in water, marinated in SH agent and marinated in water after marinating in SH agent. The results certified that the tension and elongation of wheat straw with 1 condyle is more than wheat straw without condyle, and the SH agent enhanced the tension and elongation of wheat straw. (3) SEM’s photos are used to observe the microstructure of original wheat straw and wheat straw marinated in SH agent. Leica QWin5000 software is used to calculate and analyze SEM’s photos. The results show that the pore proportion of wheat straw marinated in water is bigger than original wheat straw, and the reason is that SH agent infiltrated in the pores of wheat straw. (4) Unitary regression analysis is used to study the correlation between mechanical indices and microstructure parameters. The results certified the pore ratio greatly correlate with tension and elongation, and they can well explain the micro-mechanism of variation of mechanical parameters. (5) Some test concepts, wheat straw used for new reinforced material solidify saline soil in inshore, are submitted for studying the mechanism of strength increasing.
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