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| Volume change of triaxial soil samples based on photogrammetry technology
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| （1. College of Civil and Architectural Engineering, Guilin University of Technology, Guilin, Guangxi 541004, China; 2. Guangxi Key Laboratory of Geomechanics and Geotechnical Engineering, Guilin University of Technology, Guilin, Guangxi 541004, China）
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Abstract Based on the new photogrammetry technology, the calculation results of the soil sample marker coordinates were corrected by the least square method and the refractive correction coefficient, and the three-dimensional coordinates of the soil sample deformation were calculated. The boundary function method was used in MATLAB software to calculate the volume change data of each part of the soil sample. According to this principle， the unconsolidated and undrained（UU） tests of saturated red clay samples from Guilin, Guangxi under different confining pressures were carried out. The test results show that the "true deformation measurement" of the soil sample in different deformation stages can be completed by photogrammetry, and the deviator stress of the soil sample is 5.7% smaller than that of the conventional measurement method. The overall and local volume change data of the soil sample under non-uniform deformation are obtained by the new photogrammetry technology, which can take into account both measurement and reduction of 3D model of soil sample, and the non-contact volume change data measurement is realized.
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Received: 08 November 2021
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