【作者】 蒋红英；

【导师】 苗天德；

【作者基本信息】 兰州大学 ， 地质工程， 2006， 博士

【摘要】 颗粒材料的力学性质本质上不同于连续介质,它的研究是当前岩土工程学、力学和物理学等领域新兴的前沿课题之一,有着重要的工程应用前景和基础科学意义,本文作者在阅读和分析文献资料的基础上,以散体材料岩土结构为背景,开展了散体颗粒材料的实验与分析研究,探讨了如何将颗粒介质的力学特性与散体结构工程的设计结合起来的问题。 1、设计并开展了大尺度颗粒(钢球、砾(碎)石)三维堆体受集中荷载作用时的定量实验,统计和分析了颗粒堆对荷载力的响应情况,研究了颗粒堆内部力传递的扩散加传导效应、分布特性、力链形成、各种物理特性对力传递与分布的影响、搭拱效应作用下最大横向挤压力出现的位置、侧峰现象、低围压和高围压下颗粒堆内主要的应变形式、力峰值的变迁规律、有序对称密实排列和无序堆积中力传递路径的不同,以及力随着深度衰减的规律。 2、运用随机理论分析实验结果。研究实验值的涨落区间,以及设备和人工因素对实验的影响。建立了与实验结果在定性上相吻合的二维颗粒堆中力传递的模型及其随机方程,应用该模型描述了力随颗粒堆深度分布的变化及衰减规律,并初步探讨了建立三维颗粒堆中力传递模型的可能性。 3、研究颗粒材料应用于地基加固的工程响应特性及各种影响因素下的传力特性,探讨了不同于传统连续介质理论设计思想的散体材料工程参数设计方法,分析了散体结构的破坏机理,并尝试提出了铁路路基在运营中的有关力学问题。更多还原

【Abstract】 Mechanical properties of granular materials are essentially different from those of continuous materials. Being a new challenge in the geotechnical engineering, mechanics and physics , to investigate them is significant for the study of fundamental science and has a wide prospect of engineering application. On the basis of observation and analysis of numerous relevant literatures, the author carried out many experimental and theoretical investigations and discussed how to combine mechanical properties of granular media with the configuration problems in the geotechnical engineering, taking the collections of granular materials in the geotechnical engineering as the background.1、 Many experiments on the three-dimensional piles with large-sized particles (such as steel beads , gravel and crushed ston s) submitted to compressive load, were designed and carried out. The statistic analysis of the collective response of the piles is performed in detail. The outer envelope of the response, the distribution of the force, the evolvement of stress chains, the influence of physical behaviors on the response, the position of the maximal transverse pressure under arching effects, side peak phenomenon , major forms of the strain within the granular pile under low-and-high-surrounding pressure, changing of force peak, difference in force transmission through the granular pile between orderly symmetric dense arranging and disorderly piling, and attenuation degree of the force with the depth are presented . 2、 The experimental processes are analyzed with stochastic theory.The fluctuant range of experimental peak values, influence of equipment and manual factors on the experiment, and forcetransmission model are investigated. A two-dimensional model which is well consistent with the experimental results qualitatively and describes the attenuation law of force along the depth in the granular piles is established. Furthermore, a three-dimensional model of force transmission was discussed.3> The characteristics of engineering response in strengthening the groundwork by granular materials and various influences on force transmission are investigated. The design method of engineering parameters in granular materials which is quite different from conventional continuum was discussed. The destruction mechanism of the construction with granular materials was analyzed, and the problem of static characteristics of railroad bed was tentatively presented.更多还原