桩基分布式光纤检测技术规范初探

发布时间：2018-10-31 07:21

【摘要】：桩基检测是确保桩基工程质量一项不可缺少的工作。分布式光纤感测技术作为一种新型的检测技术,近十年来已在桩基检测中不断得到应用和推广,越来越得到许多工程单位的认可,并积累了大量的工程经验。为了规范这一技术在桩基检测中的应用,编写桩基分布式光纤检测技术规范十分必要。本文在总结国内外相关成果的基础上,结合课题组十余年来在桩基分布式光纤检测方面的研究成果和经验,对桩基分布式光纤检测技术的原理、方法、规格、适用范围、感测光缆种类与性能、布设与安装、数据处理、桩基内力分析等进行了比较系统的总结,最后初步形成了桩基分布式光纤检测技术规范。论文的主要成果如下：(1)对常用的桩基检测技术的优缺点进行了分析,介绍了基于布里渊散射光感测原理的桩基分布式光纤检测技术的优点、应用现状和发展趋势,阐明了制定桩基分布式光纤检测技术规范的重要性。(2)详细介绍了桩基分布式光纤检测技术中BOTDR、BOTDA、BOFDA三种分布式光纤感测技术的原理、解调仪及其技术指标,并对这三种光纤感测技术进行了对比分析。(3)介绍了桩基分布式光纤检测技术的检测原理；分析了桩基础受竖向荷载作用和水平荷载作用下的承载特性；采用荷载传递法分析了桩身变形规律；根据光纤应变测试结果,给出了桩身轴力、桩身压缩变形、各土层摩阻力、桩端阻力、桩身弯矩和挠度的计算公式。(4)详细介绍了桩基检测感测光缆的种类、性能和使用范围,给出了桩基分布式感测光缆的选择标准,提出了感测光缆的率定方法,并结合试验对几种常用的感测光缆进行了率定。(5)针对灌注桩、预制桩和钢管桩的自身特点,提出了多种感测光缆的布设工艺；在桩基检测中需要进行温度补偿的情况下,提出了桩基温度补偿传感器的布设方案和工艺。(6)研究并构建了桩基分布式光纤检测系统,并给出了感测光缆的质量评价标准。(7)提出了桩基分布式光纤检测的数据处理方法；分析了常见的桩基检测曲线,并归纳出了桩基常见的承载力传递规律；结合地质资料和施工记录,分析了影响桩基完整性的主要因素,得出了桩基相关质量问题的检测曲线变化规律。(8)根据桩基分布式光纤检测技术的研究成果和实践,参照中华人民共和国行业标准《建筑桩基检测技术规范》,初步形成了桩基分布式光纤检测技术规范感测光缆。
[Abstract]:Pile foundation inspection is an indispensable work to ensure the quality of pile foundation engineering. As a new type of detection technology, distributed optical fiber sensing technology has been applied and popularized in pile foundation detection in the past ten years. It has been recognized by many engineering units and accumulated a lot of engineering experience. In order to standardize the application of this technique in pile foundation detection, it is necessary to compile the technical specification for pile foundation distributed optical fiber detection. On the basis of summarizing the related achievements at home and abroad and combining the research results and experiences of the research group in the field of pile foundation distributed optical fiber detection in the past ten years, this paper introduces the principle, method, specification and applicable scope of the distributed optical fiber detection technology for pile foundation. The types and properties of sensing optical cables, placement and installation, data processing, internal force analysis of pile foundation are summarized systematically. Finally, the technical specification of distributed optical fiber detection for pile foundation is preliminarily formed. The main achievements are as follows: (1) the advantages and disadvantages of the commonly used pile foundation detection techniques are analyzed, and the advantages, applications and development trends of the distributed optical fiber detection technology based on Brillouin scattering light sensing principle are introduced. In this paper, the importance of establishing the technical specification of distributed optical fiber detection for pile foundation is expounded. (2) the principle, demodulation instrument and technical index of BOTDR,BOTDA,BOFDA distributed fiber sensing technology in pile foundation distributed fiber detection technology are introduced in detail. The three kinds of fiber sensing techniques are compared and analyzed. (3) the principle of pile foundation distributed optical fiber detection technology is introduced. The bearing characteristics of pile foundation under vertical load and horizontal load are analyzed, and the deformation law of pile body is analyzed by load transfer method. Based on the results of the fiber strain test, the formulas for calculating the axial force, compression deformation, friction resistance, pile tip resistance, bending moment and deflection of the pile body are given. (4) the types of sensing cables for detecting the pile foundation are introduced in detail. Performance and application range, the selection standard of distributed sensing cable for pile foundation is given, the method of determining the rate of sensing cable is put forward, and several commonly used sensing cables are determined in combination with test. (5) aiming at the cast-in-place pile, The characteristics of prefabricated pile and steel pipe pile are analyzed. Under the condition that the temperature compensation is needed in the testing of pile foundation, the layout scheme and technology of the temperature compensation sensor for pile foundation are put forward. (6) the distributed fiber optic detection system for pile foundation is studied and constructed. The quality evaluation standard of sensing fiber cable is given. (7) the data processing method of pile foundation distributed optical fiber detection is put forward. The common testing curves of pile foundation are analyzed, and the common bearing capacity transfer law of pile foundation is summarized. Combined with geological data and construction records, the main factors affecting the integrity of pile foundation are analyzed, and the change rule of testing curve of pile foundation related quality problem is obtained. (8) according to the research results and practice of pile foundation distributed optical fiber detection technology, According to the industry standard of the people's Republic of China, the distributed fiber optic fiber detection technology specification for pile foundation is formed.
【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU473.1

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