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适用于显微CT扫描的微型动三轴仪研制与试验验证

蒋明镜, 吕雷, 石安宁, 曹培, 吴晓峰

蒋明镜, 吕雷, 石安宁, 曹培, 吴晓峰. 适用于显微CT扫描的微型动三轴仪研制与试验验证[J]. 岩土工程学报, 2020, 42(S1): 214-218. DOI: 10.11779/CJGE2020S1042
引用本文: 蒋明镜, 吕雷, 石安宁, 曹培, 吴晓峰. 适用于显微CT扫描的微型动三轴仪研制与试验验证[J]. 岩土工程学报, 2020, 42(S1): 214-218. DOI: 10.11779/CJGE2020S1042
JIANG Ming-jing, LÜ Lei, SHI An-ning, CAO Pei, WU Xiao-feng. Development of miniature dynamic triaxial apparatus for microct scanning and its experimental verification[J]. Chinese Journal of Geotechnical Engineering, 2020, 42(S1): 214-218. DOI: 10.11779/CJGE2020S1042
Citation: JIANG Ming-jing, LÜ Lei, SHI An-ning, CAO Pei, WU Xiao-feng. Development of miniature dynamic triaxial apparatus for microct scanning and its experimental verification[J]. Chinese Journal of Geotechnical Engineering, 2020, 42(S1): 214-218. DOI: 10.11779/CJGE2020S1042

适用于显微CT扫描的微型动三轴仪研制与试验验证  English Version

基金项目: 

国家自然科学基金重大项目 51890911

国家自然科学基金重点项目 51639008

国家重点研发计划项目 2019YFC0312304

详细信息
    作者简介:

    蒋明镜(1965— ),男,教授,博士生导师,主要从事天然结构性黏土、砂土、非饱和土、太空土和深海能源土宏微观试验、本构模型和数值分析研究。E-mail:mingjing.jiang@tju.edu.cn

  • 中图分类号: TU435

Development of miniature dynamic triaxial apparatus for microct scanning and its experimental verification

  • 摘要: 土体的微观结构对其宏观力学性质有着很大的影响,为了能更深入研究土体在循环荷载作用下的微观结构演化与其宏观力学特性之间的联系,研制了一种适用于工业显微CT(computerized tomography)扫描的微型动三轴仪。该仪器主要由控制采集箱系统、主机系统、气水转换器组成。其具有体积较小、试样小型化(直径×高=10 mm×20 mm)、便于操作、兼容性强等优点,可在无需改装已有CT设备前提下对试样进行旋转扫描。以丰浦砂干砂样为材料,采用微型和常规动三轴仪进行了不同围压(50,100,200,300 kPa)和循环荷载作用下的不固结不排水试验,并对测得的初始动弹性模量E0,动剪切模量Gd,阻尼比λ进行了对比分析。结果表明:微型动三轴仪测得的初始动弹性模量E0,动剪切模量Gd,阻尼比λ与常规动三轴仪测得的结果基本相近。试验结果误差较小,验证了该仪器的可靠性。
    Abstract: The microstructure of soil has a great influence on the macroscopic mechanical properties. Therefore, to study the relationship between the macroscopic mechanical properties and the microstructure evolution of soil under the cyclic loading, a miniature dynamic triaxial apparatus is developed, which is suitable for industrial micro CT (computerized tomography) scanning. The apparatus is mainly composed of the acquisition control system, loading device system, and air-liquid converter. It has the advantages of small volume, miniaturization of the specimen (diameter × height=10 mm×20 mm), convenient to operate, strong compatibility, and the specimen can be rotating-scanned without refitting the existing CT equipment. By using the miniature dynamic triaxial apparatus and conventional dynamic triaxial apparatus, a series of unconsolidated-undrained triaxial tests on Toyoura sand under cyclic loading and different confining pressures (50, 100, 200 and 300 kPa) are carried out, and the initial dynamic elastic modulus (E0), dynamic shear modulus (Gd) and damping ratio (λ) are comparatively analyzed. The results show that the experimental curves of the initial dynamic elastic modulus (E0), dynamic shear modulus (Gd) and damping ratio (λ) exhibit a similar evolution. The difference of experimental data is small, thus, the reliability of the miniature dynamic triaxial apparatus is verified.
  • 感谢张家港晟泰克智能仪器有限公司对微型动三轴仪的加工制作,及负责人蒋敏华,软件研发部门黄兴、邵斌斌,机械设计制作部门盛文佳、李志宏等对工作的协助和配合。感谢天津大学沈振义、庞红星、尹福顺和张仕伟硕士在论文修改中提出的宝贵意见。
  • 图  1   微型动三轴仪主体结构

    Figure  1.   Main components of miniature dynamic triaxial apparatus

    图  2   控制采集箱系统

    Figure  2.   Acquisition control system

    图  3   微型动三轴主机示意图

    Figure  3.   Schematic of miniature dynamic triaxial apparatus

    图  4   轴向动应变时程曲线示例图

    Figure  4.   Curves of dynamic strain vs. time

    图  5   微型与常规动三轴仪试样

    Figure  5.   Miniature and conventional dynamic triaxial specimens

    图  6   动剪切模量与动剪应变关系曲线

    Figure  6.   Relationship between dynamic shear modulus and dynamic shear strains

    图  7   1/Edεd关系曲线

    Figure  7.   Relationship between 1/Ed and εd

    图  8   滞回圈曲线

    Figure  8.   Curves of hysteresis loop

    表  1   日本丰浦砂物理性能参数

    Table  1   Physical parameters of Toyoura sand

    试样土粒相对密度Gs平均粒径D50/mm不均匀系数Cu最大孔隙比emax最小孔隙比emin
    丰浦砂2.650.21.320.9770.597
    下载: 导出CSV

    表  2   试验方案

    Table  2   Experimental schemes

    序号试验仪器试样干密度ρd/(g·cm-3)频率f/Hz围压σ3/kPa
    1微型丰浦砂1.4830.250,100,200,300
    2常规丰浦砂1.4830.250,100,200,300
    下载: 导出CSV

    表  3   动剪切模量与动剪应变

    Table  3   Dynamic shear modulus and dynamic shear strains

    微型动三轴仪常规三轴仪相对误差/%
    动剪应变γd/%动剪切模量Gd/kPa动剪应变γd/%动剪切模量Gd/kPa
    0.0125080.012534.44.9
    0.0314080.031387.25.4
    0.062264.80.062286.47.5
    0.12217.60.122305.4
    0.251700.25177.494.2
    0.5133.80.5140.694.9
    269.43270.311.3
    下载: 导出CSV

    表  4   初始动弹性模量

    Table  4   Initial dynamic elastic moduli

    围压初始动弹性模量E0/MPa相对误差/%
    微型动三轴仪常规三轴仪
    501.431.374.2
    1002.502.384.8
    20014.2913.704.1
    30017.8617.830.2
    下载: 导出CSV

    表  5   不同围压条件下阻尼比

    Table  5   Damping ratios under different confining pressures

    围压阻尼比 λ相对误差/%
    微型动三轴仪常规动三轴仪
    500.23660.23490.6
    1000.24290.25273.8
    2000.25720.27456.3
    3000.27170.28314.0
    下载: 导出CSV
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出版历程
  • 收稿日期:  2020-05-31
  • 网络出版日期:  2022-12-07
  • 刊出日期:  2020-10-31

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