TY - GEN
T1 - Photogrammetry for volume change measurement in unsaturated soil tests
AU - Lim, B. J.M.
AU - Leong, E. C.
PY - 2014
Y1 - 2014
N2 - Measurement of volume change in soil tests is important. For saturated soil tests, this can be achieved in a number of ways: (1) measurement of axial and radial deformations and computing the volume change by assuming a uniform deformation, (2) measurement of the volume of water expelled from the soil specimen, and (3) measurement of the changes in volume of confining water under a constant pressure. However, volume change measurement becomes challenging for unsaturated soils. Firstly, air and water are involved which have very different compressibilities;- secondly, the compressibility of air is dependent on pressure and temperature, and air may also go into solution under pressure;- And lastly, volume change in unsaturated soils is usually smaller than that in saturated soils. Photogrammetry makes use of photographic images to obtain geometric properties of an object. When applied to soil tests, there are multiple challenges. The soil specimen is usually tested in a chamber which is filled with water under pressure. Besides problems with lighting and refraction which are well-known in photography, a clear image of the soil specimen is made difficult by the drainage tubes and the structure of the chamber. The objective of this paper is to evaluate photogrammetry for volume change measurement of unsaturated soil tests. Volume change measurement of soil specimens under isotropic consolidation was measured with photogrammetry and traditional method. The error of the volume change measurement from photogrammetry was found to be 100 mm+ADw-sup+AD4-3+ADw-/sup+AD4-. Therefore, photogrammetry can be applied to unsaturated soil tests where the volume change is expected to be greater than 100 mm+ADw-sup+AD4-3+ADw-/sup+AD4-.
AB - Measurement of volume change in soil tests is important. For saturated soil tests, this can be achieved in a number of ways: (1) measurement of axial and radial deformations and computing the volume change by assuming a uniform deformation, (2) measurement of the volume of water expelled from the soil specimen, and (3) measurement of the changes in volume of confining water under a constant pressure. However, volume change measurement becomes challenging for unsaturated soils. Firstly, air and water are involved which have very different compressibilities;- secondly, the compressibility of air is dependent on pressure and temperature, and air may also go into solution under pressure;- And lastly, volume change in unsaturated soils is usually smaller than that in saturated soils. Photogrammetry makes use of photographic images to obtain geometric properties of an object. When applied to soil tests, there are multiple challenges. The soil specimen is usually tested in a chamber which is filled with water under pressure. Besides problems with lighting and refraction which are well-known in photography, a clear image of the soil specimen is made difficult by the drainage tubes and the structure of the chamber. The objective of this paper is to evaluate photogrammetry for volume change measurement of unsaturated soil tests. Volume change measurement of soil specimens under isotropic consolidation was measured with photogrammetry and traditional method. The error of the volume change measurement from photogrammetry was found to be 100 mm+ADw-sup+AD4-3+ADw-/sup+AD4-. Therefore, photogrammetry can be applied to unsaturated soil tests where the volume change is expected to be greater than 100 mm+ADw-sup+AD4-3+ADw-/sup+AD4-.
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U2 - 10.1201/b17034-234
DO - 10.1201/b17034-234
M3 - Conference contribution
AN - SCOPUS:84901619901
SN - 9781138026902
T3 - Unsaturated Soils: Research and Applications - Proceedings of the 6th International Conference on Unsaturated Soils, UNSAT 2014
SP - 1605
EP - 1610
BT - Unsaturated Soils
PB - Taylor and Francis - Balkema
T2 - 6th International Conference on Unsaturated Soils, UNSAT 2014
Y2 - 2 July 2014 through 4 July 2014
ER -