一种新型光纤光栅局部位移计在小应变测量中的应用

徐东升

doi:10.11779/CJGE201707020

一种新型光纤光栅局部位移计在小应变测量中的应用 English Version

徐东升

华中科技大学土木工程与力学学院,湖北武汉 430074

基金项目: 国家自然科学基金项目（51508215）; 中央高校基本科研业务费专项资金资助项目（2017KFYXJJ138）

详细信息

作者简介:
徐东升(1985- ),男,博士,主要从事光纤传感器在岩土中应用方面的科研。E-mail: dsxu@hust.edu.cn。

计量
- 文章访问数: 0263
- HTML全文浏览量: 0
- PDF下载量: 0360
出版历程
- 收稿日期: 2016-04-14
- 发布日期: 2017-07-24

New fiber Bragg grating sensor-based local displacement transducer for small strain measurements of soil specimens

XU Dong-sheng

School of Civil Engineering and Mechanics, Huazhong University of Science and Technology, Wuhan 430074, China

摘要

摘要: 小应变下的土体模量的变化对基坑周围既有建筑物的变形和路基沉降分析具有重要意义。土体模量会随土体的应变呈非线性变化,特别是应变范围为10^-5~10^-3,土体模量随应变的增加显著降低。由于土体应变的变化范围广,传统的单一测量仪器无法连续量测土体从微小应变到小应变的模量变化情况。通常测量土体小应变模量的方法有弯曲元和局部位移计方法。弯曲元方法能有效测量土体微小应变的模量,但不能得到土体模量在小应变情况下变化规律,因为弯曲元方法无法得到和控制土体的应变。设计了基于布拉格光纤光栅传感技术的局部位移计。通过设计和标定试验,成功将布拉格光纤光栅局部位移计应用于改装的三轴试验仪器中。为进一步的对比分析,在改进的三轴试验装置中安装了弯曲元试验系统。基于改装的三轴试验仪器,进行了不同围压下的固结不排水试验,得到了土体从微小应变到小应变下模量的变化曲线。试验结果验证了光纤光栅局部位移计能有效的测量土体在小应变情况下的模量非线性变化特征。
- 光纤 /
- 布拉格光栅 /
- 局部位移计 /
- 小应变 /
- 弯曲元
Abstract: The small strain stiffness changing with soil strains is significant for the performance analysis of the existing structures subjected to the nearby excavations and subgrade settlement analysis. The soil stiffness has a nonlinear relationship with the soil strains. Especially in the strain range of 10^-5 to 10^-3, the soil stiffness dramatically decreases with the increasing soil strain. Due to the large ranges of soil strains, there is a lack of single transducer to measure the soil strains from very small strain to small strain. Two commonly used small strain measurement methods are the bender element method and the local displacement measurement method. The bender element method can obtain the soil stiffness at the very small strain level. However, it cannot obtain the relationship between the stiffness and the soil strain as it cannot control the soil strain during measurement. In this study, a new fiber Bragg grating (FBG) sensor-based local displacement transducer (LDT) is developed. After the design and calibration tests, the newly developed transducer is installed in a modified triaxial apparatus. In order to further verify the feasibility of the newly developed transducer, the bender element sensors are also incorporated in the modified apparatus. Three consolidation undrained compression tests are conducted. The test results indicate that the FBG-based LDT can be used to effectively measure the local small strains of soil specimens.
- fiber /
- fiber Bragg grating sensor /
- local displacement transducer /
- small strain /
- bender element

HTML全文

参考文献(19)

[1]	MAIR R J. Developments in geotechnical engineering research: application to tunnels and deep excavations[J]. Proceedings of the Institution of Civil Engineers-Civil Engineering, 1993, 97(1): 27-41.
[2]	TATSUOKA F A, SHIBUYA S. Deformation characteristics of soils and rocks from field and laboratory tests[C]// Proceedings of the 9th Asian Regional Conference on Soil Mechanics and Foundation Engineering. Bangkok, 1991: 77-101.
[3]	CLAYTON C R I. Stiffness at small strain: research and practice[J]. Géotechnique, 2011, 61(1): 5-37.
[4]	JARDINE R J, SYMES M J, BURLAND J B. The measurement of soil stiffness in triaxial apparatus[J]. Géotechnique, 1984, 34(4): 323-340.
[5]	BURLAND J B. Small is beautiful: the stiffness of soils at small strains[J]. Ninth Laurits Bjerrum Lecture, Canadian Geotechnical Journal, 1989, 26(4): 499-516.
[6]	HIRD C C, YUNG P C Y. The use of proximity transducers for local strain measurements in triaxial tests[J]. Geotechnical Testing Journal, 1989, 12(4): 292-298.
[7]	SCHOLEY G K, FROST J D, LO Presti D C F, et al. A review of instrumentation for measuring small strains during triaxial testing of soil specimens[J]. Geotechnical Testing Journal, 1995, 18(2): 137-156.
[8]	GOTO S, TATSUOKA F, SHIBUYA S, et al. A simple gauge for local small strain measurement in the laboratory[J]. Soils and Foundations, 1991, 31(1): 169-80.
[9]	DASARI G R, BOLTON M D, NG C W W N. Small strain measurement using modified LDTs[R]. Cambridge: Cambridge University, 1995.
[10]	YIMSIRI S, SOGA K, CHANDLER S G. Cantilever-type local deformation transducer for local axial strain measurement in triaxial test[J]. Geotechnical Testing Journal, 2005, 28(5): 445-451.
[11]	HILL K O, MELTZ G. Fiber bragg grating technology fundamentals and overview[J]. Journal of Lightwave Technology, 1997, 15: 1263-1276.
[12]	XU D S, YIN J H, CAO Z Z, et al. A new flexible FBG sensing beam for measuring dynamic lateral displacements of soil in a shaking table test[J]. Measurement, 2013, 46(1): 200-209.
[13]	BS 1377 British standard BS1377: Methods of test for soils for civil engineering purposes[S]. 1990.
[14]	BS 1377-2 Methods of test for soils for civil engineering purpose: part 2 classification tests[S]. 1990.
[15]	BS 5930 Code of practice for site investigations[S]. 1981.
[16]	PENNINGTON D S, NASH D F T, LINGS M L. Anisotropy of G 0 shear stiffness in gault clay[J]. Géotechnique, 1997, 47(3): 391-398.
[17]	LEONG E C, YEO S H, RAHARDJO H. Measuring shear wave velocity using bender elements[J]. Geotechnical Testing Journal, 2005, 28(5): 488-498.
[18]	HIGHT D W, BENNELL J D, CHANA B, et al. Wave velocity and stiffness measurements of the crag and lower london tertiaries at sizewell[J]. Géotechnique, 1997, 47(3): 451-474.
[19]	ROLLINS K M, EVANS M D, DIEHL N B, et al. Shear modulus and damping relationships for gravels[J]. Journal of Geotechnical and Geoenvironmental Engineering, 1998, 124(5): 396-405.

施引文献(6)

期刊类型引用(4)

1.	徐斌，陈柯好，王星亮，庞锐. 液化土中管道随机地震响应分析与可靠度评价研究. 岩土工程学报. 2024(01): 81-89 . 本站查看
2.	庞锐，卢韵竹，季睿，徐斌. 基于随机动力分析的高土石坝极限抗震能力研究. 岩土工程学报. 2024(10): 2237-2244 . 本站查看
3.	张冬梅，郭力，申轶尧，黄忠凯. 随机地震作用下隧道动力响应的概率密度演化分析. 岩土工程学报. 2024(S2): 21-25+37 . 本站查看
4.	庞锐，陈柯好，宋佚博，徐斌. 近断层脉冲型随机地震动模拟方法及结构动力可靠度研究. 大连理工大学学报. 2024(06): 633-640 . 百度学术