灞河河道砂砾石料工程性能试验研究

发布时间：2018-07-28 11:33

【摘要】：堤坝是水利工程的一个重要的组成部分，主要起约束河水防止水流对河岸的冲刷和保护两岸人民安全的作用，故很有必要对堤防建设质量和安全评定下大功夫。本文所据为灞河中的砂砾石，由于河流两岸分布有大量的砂砾石料，为堤防的填筑提供了天然的材料，砂砾石料具有分布广泛、储量大、排水性强、压实性好等优点，但是其本身的特性又决定了填料的不均匀性和易分散性、渗透性大等不利于工程稳定的特点。基于砂砾石的这些特点对其作深入研究使其更好的应用到工程实际中，具有很大的经济与现实意义。本文根据室内试验，得出砂砾石的基本性质，确定出砂砾石料的压实控制指标，在工程现场进行现场碾压试验，得到合理的砂砾石料松铺厚度和碾压方式、碾压遍数为工程的施工提供依据。通过试验得到：（1）通过颗粒分析试验得到当地砂砾石料的级配曲线可以看出曲线较缓，粒径分布均匀，，级配良。（2）通过相对密度试验得到最小、最大干密度随含砂量的变化曲线得到相对密度为0.6时对应的干密度，运用最小二乘多项式拟合法对数据进行处理，并结合工程实际对处理后的数据进行验证,得到在拟合次数为3时满足要求。（3）本文结合现场试验确定施工时的碾压遍数，为后续施工提供依据，对比在松铺厚度为50cm和40cm等厚度下砂砾石在不同碾压遍数下的数据，得到在松铺后度为40cm碾压遍数为6时可以满足质量和效益的要求。（4）通过大量的检测数据发现，碾压后干密度随粗料含量的增加而增加（粗料含量较小时），当粗料含量到达一定的值时干密度反而随粗料含量的增加而减小，这个干密度达到最大值时粗料含量为最优粗粒含量，不同类型的砂砾石的最优粗粒含量大都在70%左右。（5）试料含水量对碾压程度有很大作用，两者之间有一定的关系，即在绝对不含水下外部作功只是克服颗粒间的摩擦力；在颗粒间含有少量的水分时一部分外部功消耗在水分子之间的粘结力上；在含水量在最佳值时水分对颗粒有润滑作用；但是超过这个值时含水又会吸收一部分外部功。含水量主要存在于细料中，但是其起作用的细料含量在一定的范围内才较敏感，在本文中得到含水量在含砂量较大时对碾压的影响较小。
[Abstract]:Embankment is an important part of water conservancy project, which mainly restrains the river water from scouring the riverbank and protects the safety of people on both sides of the bank. Therefore, it is necessary to make great efforts to evaluate the quality and safety of dike construction. This paper is based on the sand and gravel in the Bahe River. Because there are a lot of sand and gravel on both sides of the river, it provides natural materials for the embankment construction. The sand and gravel materials have the advantages of wide distribution, large reserves, strong drainage, good compaction, and so on. However, its own characteristics determine the heterogeneity and dispersibility of fillers, and the large permeability is not conducive to engineering stability. Based on these characteristics of sand and gravel, it is of great economic and practical significance to make a thorough study on it so that it can be better applied to engineering practice. Based on the laboratory test, the basic properties of sand and gravel are obtained, and the compaction control index of sand and gravel is determined. The field compaction test is carried out on the site of the project, and the reasonable loose spreading thickness and compaction mode of sand and gravel are obtained. The number of rolling times provides the basis for the construction of the project. The results are as follows: (1) the gradation curve of the local sand and gravel is obtained by particle analysis. The curve is slow, the particle size distribution is uniform, and the gradation is good. (2) through the relative density test, the smallest is obtained. The change curve of maximum dry density with sand content obtained the corresponding dry density when the relative density is 0.6. The data are processed by least square polynomial fitting method, and the processed data are verified by engineering practice. It is obtained that the fitting times are 3 to meet the requirements. (3) in this paper, the number of rolling times in construction is determined in combination with field tests, which provides the basis for subsequent construction. Comparing the data of gravel with 50cm and 40cm in different compaction times, it is obtained that the quality and benefit can be satisfied when the degree of 40cm is 6 after loosening. (4) through a large number of test data, it is found that, The dry density increased with the increase of coarse material content (the content of coarse material was small), but decreased with the increase of coarse material content when the content of coarse material reached a certain value. When the dry density reaches the maximum, the content of coarse material is the optimum coarse grain content, and the optimum coarse grain content of different types of sand and gravel is about 70%. (5) the moisture content of the test material has a great effect on the degree of rolling compaction, and there is a certain relationship between them. That is to say, in absolute absence of underwater external work, only the friction between particles can be overcome; when there is a small amount of water among the particles, part of the external work is consumed on the adhesion between water molecules; at the optimum value of water content, the particles are lubricated by water. But above this value water absorbs some of the external work. The moisture content mainly exists in fine material, but the content of fine material is more sensitive in a certain range. In this paper, it is found that the effect of water content on compaction is small when the sand content is large.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV41

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