土体多尺度变形理论及计算分析

发布时间：2018-07-12 21:00

本文选题：跨尺度 + “基体—增强颗粒”模型　；参考：《华南理工大学》2015年硕士论文

【摘要】：关于岩土类介质的研究在近几个世纪取得了长足进步,土力学得到了广泛发展。但由于土体介质本身性质的不均匀性,土力学理论的发展始终具有很大局限性。传统上,土体往往被当做是均匀体,这与实际土体结构相悖。在土体的形成过程、环境、年代等因素都不一样的情况下,土的工程特性复杂多样,同样,其颗粒成分也非常不均匀。在宏观角度上,土体都是颗粒物组合而成,可视为均匀体,但在细观和微观角度上,组成土体的颗粒大小不一、矿物成分不同、形状各异、分布形式也不同。本文主要针对土体的尺度不均匀特性,展开了以下工作:1.探讨了跨尺度土体的试验方法,制成了“基体-增强颗粒”模型。针对以往跨尺度土体试验,发现在增强颗粒的粒径、体分比外,增强颗粒本身的分布亦对土体的性质存在很大影响。2.使用“基体-增强颗粒”模型,进行了三轴不固结不排水试验、无侧限压缩试验和直剪试验。发现随着增强颗粒提高,模型强度下降;随着体分比提高,模型强度分为提高、稳定、下降三个阶段。3.制成了具有准确分布曲线的增强颗粒,并使用实际的颗粒分布曲线求得了颗粒的统计平均粒径,发现按照实际的颗粒分布曲线计算所得统计平均粒径与假想均匀分布差异较大。4.介绍了跨尺度土体的胞元体理论,引进了相关公式,并建立了尺度应力和传统应力之间的关系式。5.推导出了三轴不排水条件下的尺度摩尔-库伦理论及尺度D-P理论,并以理论解拟合了实际试验结果。在应力空间中,给出了尺度摩尔-库伦屈服面的简图。
[Abstract]:Great progress has been made in the research of geotechnical media in recent centuries, and soil mechanics has been extensively developed. However, the development of soil mechanics theory is always limited because of the inhomogeneity of soil medium itself. Traditionally, the soil is often regarded as a homogeneous body, which is contrary to the actual soil structure. When the formation process, environment, age and other factors of soil are different, the engineering characteristics of soil are complex and diverse, and its particle composition is also very uneven. From the macro point of view, the soil mass is composed of particles, which can be regarded as homogeneous body. However, the particle size, mineral composition, shape and distribution form of the soil mass are different from the micro and micro point of view. In this paper, aiming at the scale inhomogeneity of soil, the following work is carried out: 1. The test method of cross-scale soil is discussed, and a matrix-reinforced particle model is developed. According to the past cross-scale soil tests, it is found that the distribution of the reinforced particles also has a great influence on the properties of the soil in addition to the particle size and volume fraction. Triaxial unconsolidated undrained tests, unconfined compression tests and direct shear tests were carried out using the matrix reinforced particle model. It is found that the strength of the model decreases with the increase of the particle strength, and with the increase of the volume fraction, the strength of the model is divided into three stages, I. e., increasing, stabilizing, and decreasing. The enhancement particles with accurate distribution curve were made, and the statistical average particle size was obtained by using the actual particle distribution curve. It was found that the statistical average particle size calculated according to the actual particle distribution curve was quite different from the imaginary uniform distribution. The cellular theory of cross-scale soil is introduced, the relevant formulas are introduced, and the relationship between scale stress and traditional stress is established. The scale Mole-Coulomb theory and the scale D-P theory under triaxial undrained conditions are derived, and the experimental results are fitted with the theoretical solutions. In the stress space, a simple diagram of the scale Moore-Coulomb yield surface is given.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU43

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