路基土振动压实机理研究

论文总字数：34028字

摘 要

压实是保证路基强度、耐久性、稳定性的一项重要工程措施，随着工程要求的不断提高和智能压实的出现，对路基土振动压实机理的进一步研究更加凸显其重要性。传统的振动压实机理研究多注重宏观或微观其中之一，这样单一的研究方法会与实际工况有较大差异性，模型建立会出现片面的现象。本文通过建立宏观模型和微观模型进行统一研究，主要研究内容如下：

（1）本文从土体模拟参数入手，运用方程对等法得到影响土体模拟参数计算的主要因素，并结合质弹模型对同相位振动质量的定义做出探讨；

（2）本文基于动力平衡方程建立“压路机—随振土体”的四自由度振动压实模型，考虑了随振土体质量在模型中的体现，处理了未参与振动土体对随振土体的力学作用，运用MATLAB Simulink软件仿真模拟了振动压实下的各个集中质量块的运动响应曲线，并为微观模型提供了标准运动曲线进行拟合；

（3）本文基于PFC 2D离散元软件通过半径放大法在半空间体系内生成粒径不一的密实颗粒，采用应力控制的伺服机制对颗粒材料进行周期性的振动压实，动态追踪颗粒运动过程，定义了区域化振动的概念，根据云图读取了振动压实的影响深度约在3m左右；

（4）本文通过PFC 2D软件对微观刚度从1e7至7e7遍历取值建立不同刚度下的离散元颗粒流模型，生成不同的压头运动响应曲线，通过MATLAB里的corrcoef函数进行相关性分析，定义相关性较高的曲线对应的微观刚度即为当前工况的实际微观刚度；

（5）本文根据颗粒竖直方向加速度是否大于重力加速度，水平方向水平位移是否大于2倍的竖直位移定义了振动活化颗粒，并根据振动活化颗粒累计质量量化反映了随着振动压实的不断深入，颗粒逐渐密实达到稳定状态的特性。

最后，本文对研究不足进行了探讨，并对研究成果在智能压实领域的应用进行了展望。

关键词：路基土；振动压实；耦合模型；离散元；相关性分析；振动活化区域

Abstract

Compaction is an important engineering measure to ensure the stability strength and durability of the subgrade. With the constant improvement of the engineering requirements and the emergence of intelligent compaction of subgrade, soil vibration compaction mechanism highlights the importance of further research.

The traditional research on the mechanism of vibration compaction pays more attention to one of the macroscopic or microscopic ones, so that the single research method will be quite different from the actual working conditions, and the model establishment will be one-sided.

This paper conducts a unified research by establishing macro and micro models. The main research contents are as follows:

(1) this article obtains from the simulation of soil parameter, using the equation of equivalent method to get the main factors influencing the simulation of soil parameter calculation, and combined with mass spring model on the quality of the same phase vibration definition to discuss;

(2) based on the dynamic balance equation to establish "roller - soil vibration with the" four degrees of freedom vibration compaction model, considering the vibration with the soil quality reflected in the model to deal with the soil was not involved in the vibration on the vibration with the role of soil mechanics, using MATLAB Simulink software simulation to simulate the vibration compaction under the concentrated mass movement response curve, and provides the standards for microscopic model movement curve fitting;

(3) this article is based on PFC 2D the radius amplification method in half space system to generate different particle size of solid particles, the stress control in the servo mechanism of granular material cyclical vibration compaction, dynamic tracking particle motion process, defined the concept of regional vibration, read the influence of vibration compaction based on cloud around the depth of 3 m;

(4) the micro stiffness by PFC 2D from 1 to 7 e7 traversal values to establish the particle flow code (PFC) model of discrete element under different stiffness, produce different pressure head motion response curve, through correlation analysis corrcoef function in MATLAB, define the correlation between higher as the micro stiffness curve corresponding to the current condition of actual micro stiffness;

(5) based on the particle vertical acceleration is greater than gravity acceleration, horizontal horizontal displacement is greater than 2 times of vertical displacement defines the vibration activated particles, and according to the vibration activated particles accumulated quantitative reflects the quality with the deepening of the vibration compaction, the particles gradually close-grained reach steady state characteristics.

Finally, this paper discusses the shortcomings of the research, and prospects the application of the research results in the field of intelligent compaction.

KEY WORDS: subgrade soil, vibrating compaction, coupling model, discrete element, correlation analysis, vibration-activated are

目 录

摘 要 I

Abstract II

第一章 绪论 1

1.1研究背景与意义 1

1.2国内外研究现状 1

1.2.1振动轮—土壤振动模型研究 1

1.2.2道路颗粒微观材料研究 2

1.2.3颗粒微观参数确定研究 3

1.2.4振动活化区域识别 3

1.2.5现有成果总结 3

1.3本文研究内容与技术路线 4

1.3.1研究内容 4

1.3.2技术路线 5

第二章 主要参数的确定 6

2.1基于方程对等法的土体刚度、阻尼确定 6

2.1.1方程对等法的基本原理 6

2.1.2方程对等法的模型建立 6

2.1.3方程对等法的求解 7

2.1.4推导结果的分析探讨 8

2.2压路机参数的确定 9

2.2.1压路机组成及工作原理 9

2.2.2压路机型号选取和部分模型参数确定 10

2.2.3减振器参数确定 11

2.3土体参数的确定 12

2.3.1土体参数的分类 12

2.3.2土体物理力学参数的确定 13

2.3.3振功压路饥振动轮接触面的等效圆半径的确定 13

2.3.4土体模拟参数的计算 14

2.4本章总结 15

第三章 压路机—土体耦合模型探讨分析 17

3.1振动压实宏观理论 17

3.2振动压实模型建立的意义 17

3.3“压路机—土体”振动压实四自由度模型的建立与求解 18

3.3.1模型建立的假设 18

3.3.2四自由度模型的建立 19

3.3.3基于MATLAB Simulink的仿真计算 20

3.4本章总结 25

第四章 振动压实下路基土材料的离散元模拟 26

4.1离散元方法的基本原理 26

4.1.1离散元方法的基本思想 26

4.1.2离散单元法的计算过程 26

4.1.3 PFC 2D软件中离散元分析的假设 27

4.2振动压实微观机理 27

4.3基于半径扩大法的颗粒生成方法 27

4.3.1半径扩大法的原理及意义 27

4.3.3墙体、颗粒微观参数设定 28

4.3.4生成结果显示 28

4.4压头设置 28

4.5压实过程中颗粒流运动过程仿真 29

4.5.1基于应力控制的伺服机制 29

4.5.2颗粒流区域化振动成图 30

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