周谷宇, 朱鸿鹄, 朱宝, 张诚成, 施斌. 2018: 基于光纤光栅的土体含水率快速测定试验研究. 工程地质学报, 26(6): 1439-1446. DOI: 10.13544/j.cnki.jeg.2017-388
    引用本文: 周谷宇, 朱鸿鹄, 朱宝, 张诚成, 施斌. 2018: 基于光纤光栅的土体含水率快速测定试验研究. 工程地质学报, 26(6): 1439-1446. DOI: 10.13544/j.cnki.jeg.2017-388
    ZHOU Guyu, ZHU Honghu, ZHU Bao, ZHANG Chengcheng, SHI Bin. 2018: EXPERIMENTAL STUDY ON RAPID DETERMINATION OF SOIL MOISTURE CONTENT BASED ON FIBER BRAGG GRATING TECHNIQUE. JOURNAL OF ENGINEERING GEOLOGY, 26(6): 1439-1446. DOI: 10.13544/j.cnki.jeg.2017-388
    Citation: ZHOU Guyu, ZHU Honghu, ZHU Bao, ZHANG Chengcheng, SHI Bin. 2018: EXPERIMENTAL STUDY ON RAPID DETERMINATION OF SOIL MOISTURE CONTENT BASED ON FIBER BRAGG GRATING TECHNIQUE. JOURNAL OF ENGINEERING GEOLOGY, 26(6): 1439-1446. DOI: 10.13544/j.cnki.jeg.2017-388

    基于光纤光栅的土体含水率快速测定试验研究

    EXPERIMENTAL STUDY ON RAPID DETERMINATION OF SOIL MOISTURE CONTENT BASED ON FIBER BRAGG GRATING TECHNIQUE

    • 摘要: 土体含水率与其强度、变形和渗透特性密切相关。快速测定原位土体的含水率是地基基础工程中的一个重要课题。针对现有测量方法在实时性等方面的不足,本文首次提出了一种基于光纤布拉格光栅(FBG)技术快速测定土体含水率的方法。该方法利用落球对埋设在砂土中的FBG应变传感器施加冲击荷载,获得传感器在冲击过程中的应变状态及其变化规律,在此基础上提出了峰值应变的概念;通过控制变量法,对不同含水率的砂土进行多组室内试验。试验结果表明:峰值应变随着含水率的增加而近似线性减小,因此可通过经验方程估算出土体含水率。最后分析了该方法中可能的误差来源及减小误差的方法。

       

      Abstract: Soil moisture content has a great influence on the strength, deformation and permeability of soils. How to measure soil moisture content rapidly is an important subject in foundation engineering. Aiming at the problems such as poor real-time ability in existing measurements, a new method based on fiber Bragg grating(FBG)technique for rapid determination of soil moisture content is proposed in this paper. By using free-fall balls, impact loads are applied to FBG strain sensors embedded in sandy soil. The strains and their variation of sensors in this process are measured. Based on the analysis of the variation of strain, the concept of peak strain is introduced. By controlling variable method, an indoor test on sandy soil is carried out under the condition of different moisture contents. The experimental results show that peak strain decreases with increasing of moisture content. There is a nearly linear relationship between the moisture content and the peak strain. Therefore, soil moisture content can be estimated by an empirical calculation formula. The possible errors in the method are analyzed, and the methods for reducing errors are given.

       

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