湿陷性黄土强夯动力相似关系研究

发布时间：2018-11-21 17:04

【摘要】：提出了以微结构失稳假定为依据的湿陷性黄土强夯动应力分析模型,获得了新的用于湿陷性黄土强夯模型试验设计的相似指标。采用应力波理论推导了应力波在理想化空间结构节点处的应力平衡方程,质点速度连续方程,波阵面上的动量守恒方程,得到了描述节点处入射波,透射波与反射波变化规律的物理方程。采用MATLAB编程,建立了能够计算短时间内部分结构单元的应力变化的湿陷性黄土强夯动应力分析模型。得到了反映湿陷性黄土强夯应力变化规律的关键物理量。应用相似理论和量纲分析法,推导了新的相似指标。湿陷性黄土强夯动应力分析模型可以计算短时间内部分结构单元的应力变化。计算结果符合应力波由近及远的传递规律,体现了应力波的加载与卸载过程,符合应力波随着传递距离的增加,应力逐渐减少的规律,符合弹性应力波叠加的规律。反映湿陷性黄土强夯应力变化规律的关键物理量是任一点的应力,任一点的位置坐标,夯锤的落距,夯锤的质量,夯锤的密度,夯锤的弹性模量,夯锤的底面半径,结构模型中杆件单元的弹性模量,杆件单元的密度,相邻杆件单元之间的夹角,湿陷性黄土的孔隙比,黄土对夯锤作用的侧摩阻力,时间,重力加速度。在模型与原型试验采用相同的重力加速度条件时,新的相似指标仍不易满足。
[Abstract]:A dynamic stress analysis model of collapsible loess dynamic compaction based on the assumption of microstructural instability is proposed, and a new similar index is obtained for the experimental design of collapsible loess dynamic compaction model. The stress balance equation, particle velocity continuity equation, momentum conservation equation on the surface of the wave array are derived by using the stress wave theory at the node of the idealized space structure. The incident wave at the describing node is obtained. The physical equation of the variation of transmitted and reflected waves. The dynamic stress analysis model of collapsible loess dynamic compaction can be established by using MATLAB program, which can calculate the stress change of some structural elements in a short time. The key physical quantities reflecting the law of dynamic compaction stress of collapsible loess are obtained. A new similarity index is derived by using similarity theory and dimensional analysis method. The dynamic stress analysis model of collapsible loess dynamic compaction can calculate the stress changes of some structural elements in a short time. The calculation results accord with the law of the stress wave transfer from near to far, which reflects the loading and unloading process of the stress wave, the law that the stress wave decreases gradually with the increase of the transfer distance, and accords with the law of the superposition of the elastic stress wave. The key physical quantity reflecting the law of dynamic compaction stress of collapsible loess is the stress of any point, the position coordinates of any point, the drop distance of the hammer, the quality of the hammer, the density of the hammer, the elastic modulus of the hammer, the radius of the bottom surface of the hammer. In the structural model, the elastic modulus of the member element, the density of the member element, the angle between adjacent member elements, the void ratio of collapsible loess, the lateral friction, time, and acceleration of the action of loess to the rammer are discussed. When the model and prototype test adopt the same gravity acceleration condition, the new similarity index is still difficult to satisfy.
【学位授予单位】：中国民航大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU444;TU472.31

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