地基变形光纤光栅监测可行性的试验研究

发布时间：2018-10-24 12:03

【摘要】：针对传统地基变形监测存在的监测效率低、误差大、精度低等问题,提出通过光纤光栅(FBG)技术监测地基应变分布、掌握地基变形规律的新方法.开展基于埋入式FBG应变传感器的平面应变砂土地基加载模型试验,利用粒子图像测速(PIV)技术获取模型箱侧壁地基土体的应变分布规律.监测结果表明,采用FBG技术能够灵敏地捕捉到土体在逐级荷载下的内部应变累积过程,获得的应变分布特征与PIV结果较吻合,真实反映了模型地基的变形和破坏模式,初步证明了FBG光纤监测技术应用于地基变形监测的可行性.该研究说明,PIV技术可以作为检验、标定FBG应变监测结果的辅助工具.两种监测方法在具体应变量值上有一定的差异,原因可以归结为试验误差、传感器变形耦合程度以及照相质量好坏等几个方面.
[Abstract]:Aiming at the problems of low monitoring efficiency, large error and low precision in traditional foundation deformation monitoring, a new method of monitoring foundation strain distribution by fiber Bragg grating (FBG) technology is put forward to master the law of foundation deformation. Based on the embedded FBG strain sensor, the loading model test of plane strain sand soil foundation was carried out. The strain distribution of the lateral foundation of the model box was obtained by particle image velocimetry (PIV) technique. The monitoring results show that the strain accumulation process of soil under progressive loading can be captured sensitively by using FBG technique, and the strain distribution characteristics obtained are in good agreement with the PIV results, which truly reflect the deformation and failure mode of the model foundation. The feasibility of application of FBG optical fiber monitoring technology in foundation deformation monitoring is preliminarily proved. This study shows that the PIV technique can be used as an auxiliary tool for testing and calibrating the results of FBG strain monitoring. There are some differences between the two monitoring methods in terms of the value of specific strain variables, which can be attributed to the experimental error, the coupling degree of sensor deformation and the quality of photography.
【作者单位】：南京大学地球科学与工程学院;南京大学(苏州)高新技术研究院;
【基金】：国家自然科学基金资助项目(41672277,41230636) 国家重大科研仪器研制项目(41427801) 江苏省自然科学基金资助项目(BK20161238)
【分类号】：TU433

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