锚杆锚固质量动力响应特征与检测技术研究

发布时间：2018-01-25 17:07

本文关键词： 锚杆锚固质量缺陷弹性动力学动力响应有限元频谱分析现场测试　出处：《西安科技大学》2013年博士论文　论文类型：学位论文

【摘要】：锚杆锚固质量缺陷检测技术研究是岩土锚固工程中的重要研究课题之一，开展锚杆锚固质量动力响应特征与检测技术研究具有重要的理论意义和工程应用价值。本文通过理论分析、数值计算和现场测试相结合的手段开展工作，，主要结论有： ⑴基于弹性动力学理论，建立了缺陷锚杆锚固质量的动力响应模型，分析了完全锚固锚杆和缺陷锚杆锚固质量的动力响应特征。结果表明，完全锚固锚杆动力响应特征具有空间性和时间性，即同一时间不同位置的位移、振动速度不同，同一位置不同时间的位移和振动速度不同；对于缺陷锚杆锚固体，应力波的振动速度、振幅变化较大，在不同缺陷程度的接触界面处振幅和速度将会发生突变，缺陷程度越严重，其突变幅度越大。 ⑵利用有限元对频率分别为f=1000、2000、3900、6000、7000、8000Hz激发波产生的应力波在锚杆中传播特性以及不同密度、弹性模量的锚杆锚固体动力响应特征进行了数值模拟。结果表明；频率1000~8000Hz之间存在一个最佳激发波；锚杆锚固体的密度和弹性模量与应力波的位移、速度成正比；激发波频率相同的情况下，锚杆锚固体的密度和弹性模量越小，底端反射出现的周期越多。 ⑶利用傅里叶变换进行了频谱分析，确定了动力测试信号的主频；完成了不同频率范围锚杆锚固质量动力测试信号滤波分析。结果表明，当滤波的频谱为主频某一范围时，能大幅度消除干扰波，滤波效果最佳。 ⑷现场测试研究表明，当锚杆锚固体长度小于某一长度时或大于某一长度时，不能从动力测试信号中识别该长度，即锚杆锚固质量动力测试信号识别技术存在盲区。应力波在两个单面焊接锚杆中传播时，应力波只传播到第一个锚杆底部而不会向第二根锚杆继续传播；应力波在中部横向焊接在其它结构物的锚杆中传播时，应力波不会受其焊接影响而继续向前传播。
[Abstract]:The research of bolt anchoring quality defect detection technology is one of the important research topics in geotechnical anchoring engineering. It is of great theoretical significance and engineering application value to study the dynamic response characteristics and detection technology of anchor mass. This paper works through the combination of theoretical analysis, numerical calculation and field testing. The main conclusions are: 1 based on the theory of elastic dynamics, the dynamic response model of the anchoring quality of the defective anchor rod is established, and the dynamic response characteristics of the anchoring quality of the complete anchor rod and the defective anchor rod are analyzed. The dynamic response of the fully anchored anchor rod has the characteristics of space and time, that is, the displacement at different positions at the same time has different vibration velocities, and the displacement and vibration velocities at different times at the same time. The vibration velocity and amplitude of the stress wave change greatly for the anchor body with defects, and the amplitude and velocity of the stress wave will change at the contact interface of different degree of defect. The more serious the defect degree, the greater the amplitude of the sudden change. (2) the stress wave propagation characteristics and different density of the stress wave generated by the excitation wave of 6000 ~ (000) ~ (7 000) ~ (000) Hz are obtained by using the finite element method (FEM) in the Anchorage. The dynamic response characteristics of anchors with elastic modulus are numerically simulated. There is an optimal excitation wave between 1000 and 8, 000 Hz. The density and elastic modulus of anchors are proportional to the displacement and velocity of stress waves. Under the same excitation frequency, the smaller the density and elastic modulus of the anchor, the more the period of reflection at the bottom. (3) the main frequency of the dynamic test signal is determined by Fourier transform. The results show that the interference wave can be eliminated greatly and the filtering effect is the best when the frequency spectrum of the filter is a certain range of the main frequency. The field test results show that when the length of anchor bolt is less than a certain length or larger than a certain length, the length can not be identified from the dynamic test signal. When the stress wave propagates in two one-sided welded anchors, the stress wave only propagates to the bottom of the first anchor and does not continue to propagate to the second anchor. When the stress wave propagates in the transverse welding of the middle part in the anchors of other structures, the stress wave will not be affected by its welding and will continue to propagate forward.
【学位授予单位】：西安科技大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU476

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