透明土的透明度及其对可视化实验技术的影响

发布时间：2018-06-05 16:56

本文选题：透明土 + 透明度　；参考：《浙江大学》2017年硕士论文

【摘要】：透明土是由透明固体颗粒及与其折射率相匹配的透明孔隙流体所组成的两相介质。其中,透明的固体颗粒、孔隙流体分别代表了天然的土颗粒、孔隙流体的各类特性。因此,透明土被广泛地应用于土工试验中对天然土体的岩土力学特性的模拟。迄今为止,不同学者采用不同的配方配置了不同特性的透明土,各类透明土均可在一定程度上有效地模拟天然土体的物理力学特性。基于透明土对天然土体的有效模拟,可对土体内部进行非介入式、无损和连续的测量,相比于岩土工程传统测量方法可避免传感器刚度、尺寸等对试验结果的干扰,能更全面地观测到内部的土颗粒的运动特征,同时相比于X射线扫描和核磁共振等其它非介入式测量方法,透明土测量更经济、直观且易于操作。在透明土可视化实验技术中,数字图像采用DIC(DigitalImageCorrelation,数字图像相关方法)进行数据处理。鉴于成像质量及DIC分析的准确性均与透明的透明度有关,因此本文针对透明土的透明度提出了参数化的客观评价方法。在总结国内外研究的基础上,以熔融石英砂作为透明土的固体颗粒,以白矿物油和溶剂油的混合物作为孔隙流体,从而配置了熔融石英砂透明土,并在本文中对透明土的透明度及其对可视化实验技术的影响进行了如下研究:(1)基于光度学原理定义的透射率来定量评价透明土的透明度。首先提出了透射率的计算原理及测量方法,进一步通过克里斯欣森效应的规律研究了固液折射率匹配程度和透光厚度对透明土透射率变化的影响,并发现了透明土中气泡对提高透射率的不利作用。(2)探究了透明土的透明度对可视化实验技术的影响:一方面,将熔融石英砂透明土透射率测量结果与相应透明度效果图的清晰度评价函数相关联,建立了透明土的透明度与可视化实验技术中成像质量的联系;另一方面,通过标定不同透射率的透明土其DIC测量的精度,揭示了透明土的透明度与DIC测量精度间的关系。试验发现,透明土的透明土对DIC分析精度具有双重影响,一方面透明度提高有利于提高数值图像的清晰度,从而提高DIC分析的精度;另一方面,透明度提高削弱了“滤波”作用,从而有降低了 DIC分析的精度。
[Abstract]:Transparent soil is a two-phase medium composed of transparent solid particles and transparent pore fluid matching its refractive index. Among them, transparent solid particles and pore fluids represent various properties of natural soil particles and pore fluids, respectively. Therefore, transparent soil is widely used in geotechnical tests to simulate the geotechnical properties of natural soil. Up to now, different scholars have used different formulations to configure transparent soil with different properties, and all kinds of transparent soil can effectively simulate the physical and mechanical properties of natural soil to a certain extent. Based on the effective simulation of transparent soil to natural soil, non-interventional, non-destructive and continuous measurement can be carried out on the soil body. Compared with the traditional geotechnical engineering measurement method, the interference of sensor stiffness and size on the test results can be avoided. Compared with other non-interventional measurement methods such as X-ray scanning and nuclear magnetic resonance (NMR), the measurement of transparent soil is more economical, intuitive and easy to operate than that of other non-interventional measurement methods such as X-ray scanning and nuclear magnetic resonance. In the experiment technology of transparent soil visualization, the digital image is processed by DIC-Digital Image correlation (DIC-Digital Image correlation). Since the imaging quality and the accuracy of DIC analysis are related to the transparency of the transparent soil, a parameterized objective evaluation method for the transparency of the transparent soil is proposed in this paper. On the basis of summing up the research at home and abroad, the fused quartz sand is used as the solid particle of transparent soil, and the mixture of white mineral oil and solvent oil is used as pore fluid. In this paper, the transparency of transparent soil and its influence on visual experimental technology are studied as follows: 1) the transparency of transparent soil is quantitatively evaluated based on the transmittance defined by photometric principle. Firstly, the calculation principle and measurement method of transmittance are put forward, and the influence of the matching degree of refractive index of solid and liquid and the thickness of transmittance on the change of transmittance of transparent soil is studied by the law of Christensen effect. The adverse effect of bubbles on increasing transmittance in transparent soil is found. (2) the influence of transparency of transparent soil on visual experimental technology is explored: on the one hand, In this paper, the relation between the transparency of fused quartz sand and the imaging quality in visual experiment is established by correlating the measurement results of transparent soil with the clarity evaluation function of the corresponding transparency effect diagram; on the other hand, the relationship between the transparency of the transparent soil and the imaging quality in the visualization experiment is established. The relationship between the transparency of transparent soil and the accuracy of DIC measurement is revealed by calibrating the accuracy of DIC measurement of transparent soil with different transmittance. It is found that the transparent soil of the transparent soil has a double influence on the accuracy of DIC analysis. On the one hand, the increase of transparency is conducive to the improvement of the clarity of the numerical image, thereby improving the accuracy of the DIC analysis; on the other hand, The improvement of transparency weakens the function of filtering and thus reduces the accuracy of DIC analysis.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU43

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