A SIMPLE GAUGE FOR LOCAL SMALL STRAIN MEASUREMENTS IN THE LABORATORY
A SIMPLE GAUGE FOR LOCAL SMALL STRAIN MEASUREMENTS IN THE LABORATORY
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DOI：
10.3208/sandf1972.31.169
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发表时间：
1991-03
影响因子：
3.7
通讯作者：
S. Goto;F. Tatsuoka;S. Shibuya;Youseong Kim;Takeshi Sato
中科院分区：
文献类型：
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作者：
S. Goto;F. Tatsuoka;S. Shibuya;Youseong Kim;Takeshi Sato
摘要：开发了一种名为“局部变形传感器 (LDT)”的简单装置来研究土壤的刚度，可以在实验室中测量 10-6 至 10-2 范围内的应变水平。首先描述了对应变（即输出电压）和轴向应变之间非线性但唯一确定的关系的理论考虑。然后根据理论和校准测试的结果讨论了LDT应变测量的准确性。使用假人检查输出电压的稳定性几天。在三轴单元中的细洁净砂上进行的各向同性固结试验中，使用 LDT 测量的内部轴向应变与无层理误差条件下的内部轴向应变非常吻合，这些应变是根据使用不同高度样本的试验结果推断出来的。此外，在平面应变压缩中，使用LDT测量的内部轴向应变与激光散斑法测量的内部轴向应变接近。 LDT 的功能已在三轴试验中得到证明，在三轴试验中，当样本受到单调和循环载荷时，在规定的应变范围内成功测量了砾石、水泥处理的砂土和软岩的杨氏模量的变化。
ABSTRACT A simple device named “local deformation transducer (LDT)” was developed to investigate stiffness of soils that can be measured in the laboratory for strain levels ranging from 10-6 to 10-2. The theoretical consideration into the non-linear, but uniquely determined, relationship between the gauge strain (i.e., output voltage) and the axial strain is first described. The accuracy of the strain measurement using LDT is then discussed based on the theory and the results of calibration tests. The stability of the output voltage was examined for a few days using a dummy. In isotropic consolidation tests performed on a fine clean sand in triaxial cells, the internal axial strains measured using LDT agreed well with those associated with the condition of no bedding error, which were extrapolated from the results of tests using the specimens with various heights. Besides, in plane strain compression, the internal axial strain measured using the LDT was close to that determined by means of a laser speckle method. The capability of the LDT has been demonstrated in triaxial tests in which the variations of Young’s modulus of a gravel, a cement-treated sandy soil and a soft rock were successfully measured for the prescribed range of strains as the specimens were subjected to both monotonic and cyclic loadings.