【作者】 李凯；

【导师】 张景科；

【作者基本信息】 兰州大学 ， 土木工程·岩土工程， 2020， 硕士

【摘要】 玻璃纤维增强塑料(GFRP,Glass-Fiber Reinforced Plastic)锚杆锚固技术在土遗址保护加固中已占据重要地位,其锚固质量影响着锚固本体的安全性。因此,对于锚固施工质量和服役期安全性的检测显得尤为重要。然而,由于土遗址的文物属性,目前破坏性的拉拔检测手段并不能满足要求。声频应力波法无损检测技术在土遗址GFRP锚杆锚固系统中的应用研究仍然处于起步阶段,且由于土遗址锚固系统介质的多样性,造成应力波的传播与反演识别较为复杂,许多问题仍未明确,从而制约了声频应力波法在土遗址GFRP锚固系统中的应用。本文在土遗址GFRP锚杆锚固施工现场调查的基础上,通过室内模型试验,结合滤波、傅里叶变换和希尔伯特-黄(HHT,Hilbert-Huang Transform)等信号处理方法,对土遗址GFRP锚杆锚固系统中的无损检测进行深入研究。主要包含以下研究成果:(1)通过对不同外露段长度和超钻深度的室内模型研究,得到了外露段长度与超钻深度对声频应力波法检测信号的影响规律,给出了外露段长度阈值,为无损检测锚固参数的设置提供了一定依据;(2)通过锚固模型浆液龄期内无损检测的研究,得出了龄期与固结波速、基频等无损检测时频特征的关系,并明确了偏孔模型与完整模型浆液龄期内时频特征差异,为锚固施工过程中的质量控制奠定了一定的基础;(3)通过设置不同锚固长度完整模型,并结合傅里叶变换、希尔伯特-黄等信号处理方法,明确了注浆完整锚固模型的希尔伯特-黄时频谱锚固长度识别方法,为土遗址GFRP锚杆锚固长度检测提供了较为系统的反演方法;(4)通过分析偏孔和局部空浆两种典型缺陷锚固模型检测信号,得出了偏孔锚固模型锚固长度反演方法以及不同空浆缺陷锚固系统的时频特征规律,并结合希尔伯特-黄信号处理方法,明确了锚固系统中空浆缺陷位置反演的方法。此外,利用完整模型与空浆缺陷模型杆底反射时间差异,给出了反演空浆缺陷大小的方法。为土遗址GFRP锚杆锚固系统中空浆缺陷的检测提供了依据。更多还原

【Abstract】 Technology of GFRP anchoring has occupied an important position in the consolidation and conservation of earthen sites,and its anchoring quality affects the safety of the earthen sites.Therefore,it is particularly important to inspect the quality of anchorage construction and safety during service.However,due to the earthen sites are cultural relics,the current methods of pulling detection are far from meeting the requirements for earthen sites.And the application of acoustic frequency stress wave non-destructive testing technology is still in its infancy in the GFRP bolt anchoring system of earthen sites,and due to the diversity of media in the anchorage system of earthen sites,the propagation of the stress wave and the identification of the inversion are complicated.Many questions remain unclear,which restricts the application of the acoustic stress wave method in the GFRP bolt anchoring system of earthen sites.Based on the field investigation of GFRP bolt anchoring construction in earthen sites,Through the indoor model test,combined with filtering,Fourier transform and Hilbert Huang signal processing methods,this paper studies the non-destructive testing of GFRP bolt anchoring system in earth sites,,It mainly includes the following research results:(1)Through the study of indoor models with different exposed sections and anchor slurry at the bottom of the bolt,the influence of exposed length and depth of anchor slurry at the bottom of the bolt on the detection signal of the acoustic stress wave method is obtained.The length threshold of the exposed section is given as an anchorage parameter for nondestructive testing.(2)Through the study of the nondestructive testing of the anchor model slurry age,the relationship between the age and the time-frequency characteristics of nondestructive testing such as consolidation wave velocity and fundamental frequency was obtained,and the difference in time-frequency characteristics of the slurry age between the partial hole model and the complete model was clarified,laying a foundation for quality control during anchoring construction;(3)By setting complete models of different anchoring lengths and combining signal processing methods such as Fourier transform and Hilbert-Huang,the identification method of the anchoring length of the grouting complete anchoring model using the Hilbert-Huang time-spectrum was clarified.Provides a more systematic inversion scheme for the detection of the anchorage and anchorage length of GFRP bolt anchoring at earthen sites;(4)By analyzing the detection signals of two typical defect anchoring models of partial hole model and the complete model,the inversion method of the anchor length of the partial hole anchoring model and the time-frequency characteristics of grouting defect anchoring systems are obtained,combined with HHT signal processing method clarifies the inversion method of grouting defect position in the anchoring system.In addition,using the difference between the bottom reflection time of the complete model and the grouting defect model,a method for inverting the size of the grouting defect is given.It provides a basis for the detection of grouting defects in the GFRP anchoring system of earthen sites.更多还原