桩基综合检测技术研究及应用

发布时间：2018-10-18 09:15

【摘要】：桩基础作为隐蔽工程,使得桩的质量不容易把控,桩基检测工作显得尤为重要,也是工程中的重点和难点。本文主要是研究桩基检测的原理及应用,探讨分析不同检测方法得到的缺陷桩的信号特征和区别,从而正确有效地判断桩基的缺陷,给出完整性判定。本文结合福建某工程项目的建设,利用低应变反射波法、声波透射法及钻孔取芯法进行了桩基完整性评价,完成的主要工作和得到的结论如下:(1)在广泛查阅文献资料的基础上,对常用桩基完整性检测方法的概念、测试仪器和设备、检测流程及注意事项等进行了详细叙述,分析各方法的优缺点,探讨了相关技术的国内外研究发展和现状。(2)详细阐述了利用钻芯法、声波透射法和低应变反射波法进行桩基完整性检测的基础理论,包括声波与振动、波传播特点、反射透射及桩基纵向振动波动方程、反射波法桩身缺陷诊断原理等,便于检测人员在实践应用中懂得如何寻求合适的方法,减少差异,准确分析问题,使理论服务于实践。(3)介绍了低应变反射波法的准备工作、传感器安装与激振等技术,结合现行规范针对典型桩基缺陷的时域反射曲线进行了分析。阐述超声波法桩基完整性检测的声测管预埋工作、现场检测技术,对波速、波幅及PSD判据的计算作分析说明,并总结出上述物理学参数和缺陷的规律。(4)结合工程实践桩基检测工作,研究了进行声波透射法、低应变反射波法和钻芯法综合检测的必要性,定性且定量缺陷的特征和位置。每种方法都有优缺点,用不同的手段合理检测,对比分析,既能相互验证彼此的准确性,也能取长补短,有效避免不必要的漏检、误检,提高桩基检测的精度与可靠度。本文以低应变检测法从整体视察桩身质量,由它的使用特点,可以作为桩基质量普查的方法。但是其对于桩基缺陷的定性和定量描述仍显得乏力,尤其在桩身浅部有缺陷时,曲线容易失真,声波透射法恰巧可以弥补这个缺点,准确定位缺陷,通过有关声学参数的计算,定量缺陷类型也绰绰有余。然而,声波透射法仅针对所检测的剖面内有较高准确性,检测盲区若存在缺陷,还需要低应变的宏观定性。两种方法的综合应用,去伪存真,为提高检测的精确度起到锦上添花作用。
[Abstract]:Pile foundation, as a hidden engineering, makes the quality of pile difficult to control, pile foundation inspection is particularly important, but also the key and difficult point in the engineering. In this paper, the principle and application of pile foundation detection are studied, and the signal characteristics and differences of defective pile obtained by different testing methods are discussed, so that the defect of pile foundation can be judged correctly and effectively, and the integrity judgment is given. Based on the construction of a project in Fujian Province, this paper evaluates the integrity of pile foundation by means of low strain reflection wave method, acoustic wave transmission method and drilling coring method. The main work and conclusions are as follows: (1) based on the extensive reference to the literature, This paper describes in detail the concept of common pile foundation integrity testing methods, testing instruments and equipment, testing flow and points for attention, and analyzes the advantages and disadvantages of each method. The research development and present situation of related technologies at home and abroad are discussed. (2) the basic theory of pile foundation integrity detection by drilling core method, acoustic wave transmission method and low strain reflection wave method is described in detail, including acoustic wave and vibration, wave propagation characteristics. The reflection transmission and longitudinal vibration wave equation of pile foundation, the principle of pile body defect diagnosis by reflection wave method and so on, are convenient for the examiner to find suitable methods in practical application, to reduce the difference and to analyze the problem accurately. Make the theory serve the practice. (3) introduce the preparation of low strain reflection wave method, sensor installation and exciting technology, and analyze the time-domain reflection curve of typical pile foundation defects according to the current code. This paper describes the work of acoustic pipe embedded in ultrasonic pile foundation integrity testing, the field detection technology, and the calculation of wave velocity, amplitude and PSD criterion, as well as the analysis and explanation of the calculation of the wave velocity, amplitude and PSD criterion. The above physical parameters and defects are summarized. (4) combined with the engineering practice of pile foundation detection, the necessity of comprehensive detection of acoustic transmission method, low strain reflection wave method and core drilling method is studied, and the qualitative and quantitative defect characteristics and location are also studied. Each method has its own merits and demerits. Using different methods to detect and compare each other can not only verify each other's accuracy, but also make up for each other's shortcomings, effectively avoid unnecessary missed detection and false detection, and improve the accuracy and reliability of pile foundation detection. In this paper, the method of low strain inspection is used to inspect the quality of pile body from the whole. According to the characteristics of its application, it can be used as a method of investigating the quality of pile foundation. However, the qualitative and quantitative description of the defects of pile foundation is still weak, especially when there are defects in the shallow part of the pile, the curve is easy to be distorted, the sound wave transmission method can make up for this shortcoming, locate the defect accurately, and calculate the acoustic parameters through the calculation of the acoustic parameters. Quantitative defect types are more than adequate. However, the acoustic transmission method only has a high accuracy in the detected section. If there are defects in the blind area, the macroscopic qualitative analysis of low strain is needed. The combined application of the two methods can improve the accuracy of detection by discriminating false objects and retaining real things.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TU473.1

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