基于盒维数的锚杆锚固质量无损检测研究

发布时间：2018-03-28 03:28

本文选题：锚杆　切入点：无损检测　出处：《太原理工大学》2015年硕士论文

【摘要】：锚杆作为支护手段，在众多的城市基础设施建设、地铁隧道桥梁等工程项目，以及矿井建设等工程领域中发挥着举足轻重的作用。它的工作状况影响着整个工程的进度，涉及安全性、稳定性等多方面。因此，如何对锚杆的工作情况进行检测，得到理想的结果及时进行修复显得尤为关键和迫切。目前来说，众多学者经过多年研究，在锚杆无损检测领域取得了一定的成果与进步，但难点就是如何准确快速识别底端反射，这个问题直接导致了他们的研究成果无法在实际中广泛应用。另外实验室研究的假设条件与实际中的工程应用有着较大的差别，现有的理论能否满足绝大多数的实际工程应用仍有待商榷。针对目前遇到的难题，本文对锚杆无损检测的理论基础做了深入的研究，对杆体内应力波的传播规律做了新的探索，对分形以及盒维数的原理和适用范围也做了深入探索。基于以上理论研究，将分形盒维数计算方法大胆的应用于锚杆无损检测工程领域，，通过实验室研究，提出了合适的盒维数数学计算模型，利用MATLAB语言进行了相关计算程序的编写。最终通过实验研究，用采集到的数据进行研究发现了盒维数与锚杆工作荷载之间的关系，得出了相应的相应曲线，并且分析论证了该方法的可行性。通过本文的研究，在锚杆无损检测领域取得了如下的一些成果与进步： 1）初步建立了较为完整的锚杆锚固质量评价体系，提出了全面结合七个不同参数（衰减系数、幅值比、有效锚固长度、固结波速、频率比、基频及基频点的动刚度）合力判断锚杆锚固质量的方法。 2）深入研究了分形理论以及具体的盒维数理论，结合数学和实际应用两方面建立了详尽的数学计算模型，并且从理论上和适用范围两方面论证了锚杆无损检测与分形盒维数结合的合理性与可行性； 3）建立了分形盒维数的锚杆无损检测数学模型，利用MATLAB语言进行了程序编写，利用二者可以准确的计算出加速度响应曲线的盒维数数值大小，导入origin软件进行拟合，得出锚杆在荷载作用下激发收集到的响应曲线的盒维数与锚杆工作荷载之间的曲线关系； 4）不同的试件，拟合出的荷载——盒维数曲线趋势基本一致，都是先增大，到达峰值后减小。相同锚固参数的试件盒维数数值有差异，但是达到盒维数最大值的荷载相同。 5）通过荷载——盒维数曲线，可以直观的判断锚杆的锚固质量以及它的极限荷载：当盒维数数值位于最高点值前面的时候，可以认为锚杆还近似处于弹性变形阶段；当盒维数数值与最高点值相等或者非常接近的时候，可以认为锚杆处于锚固失效阶段。
[Abstract]:As a means of supporting, bolt plays an important role in many urban infrastructure construction, subway tunnel bridge and other engineering fields, as well as mine construction, etc. Its working condition affects the progress of the whole project. Therefore, it is very important and urgent to check the working condition of anchor rod and get the ideal result to repair it in time. At present, many scholars have studied it for many years. Some achievements and progress have been made in the field of nondestructive testing of bolts, but the difficulty is how to identify the reflection at the bottom accurately and quickly. This problem directly results in their research results can not be widely used in practice. In addition, the hypothesis of laboratory research is quite different from that of practical engineering applications. Whether the existing theory can satisfy most of the practical engineering applications is still open to question. In view of the problems encountered at present, the theoretical basis of nondestructive testing of anchor rod is deeply studied in this paper, and the propagation law of stress wave in the bolt is explored in a new way. Based on the above theoretical research, the fractal box dimension calculation method is applied boldly in the field of nondestructive testing engineering of anchor rod. A suitable mathematical calculation model of box dimension is put forward, and the relevant calculation program is compiled by using MATLAB language. Finally, the relationship between box dimension and working load of anchor rod is found by the experimental study and the data collected. The corresponding curves are obtained, and the feasibility of the method is analyzed. Through the research in this paper, some achievements and progress have been made in the field of non-destructive testing of bolts. 1) A relatively complete evaluation system of anchoring quality is established, and seven parameters (attenuation coefficient, amplitude ratio, effective anchoring length, consolidation wave velocity, frequency ratio) are put forward. The method of judging anchoring quality by combining forces of fundamental frequency and dynamic stiffness of fundamental frequency points. 2) the fractal theory and the box dimension theory are deeply studied, and a detailed mathematical calculation model is established in combination with mathematics and practical application. The rationality and feasibility of the combination of nondestructive testing of bolt and fractal box dimension are demonstrated in theory and scope of application. 3) the mathematical model of the nondestructive testing of the fractal box dimension is established, and the program is compiled by MATLAB language. The box dimension value of the acceleration response curve can be accurately calculated by using the two models, and the value of the box dimension of the acceleration response curve can be accurately calculated by introducing the origin software to fit the model. The relationship between the box dimension of the response curve and the working load of the bolt is obtained. 4) for different specimens, the fitted load-box dimension curve is basically the same, which increases first, then decreases after reaching the peak value. The values of box dimension of the same Anchorage parameter are different, but the load that reaches the maximum value of box dimension is the same. 5) through the load-box dimension curve, the anchoring quality and its ultimate load can be judged intuitively: when the box dimension is in front of the highest value, the anchor rod is still approximately in the elastic deformation stage; When the box dimension is equal to or very close to the highest value, the anchor rod is considered to be in the Anchorage failure stage.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD353.6

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