【摘要】 应用基于亚像素角点识别的计算机图像处理技术,提出并实现了一种土工三轴试验试样全表面变形观测的图像测量方法。通过一台CMOS摄像机,借助放置于改制压力室中的平面反光镜,实现了对试样全表面变形的实时测量。在此基础上,对原始数据进行了畸变修正及像素当量归一化,并通过引入相邻时间间隔每个计算邻域内试样等向膨胀的计算假定,求得了试样全表面变形场。最后,以饱和砂土三轴排水剪切试验为例,探讨了全表面变形场在分析试样局部化变形中的应用。更多还原

【Abstract】 An automatic digital image processing technique is presented for whole-surface measurement of specimens’ deformations during triaxial tests.This method incorporates digital imaging techniques and computer-aided analysis to assess the deformation throughout a triaxial test.A detailed description of hardware as well as other equipment is provided.Regulated power supply along with a darkened chamber is adopted to ensure the stability of the lighting environment.Data analysis methodology including distortion correction,pixel equivalent normalization,strain field calculation and data splicing is provided.The calculation of strain is based on the assumption that in each neighborhood of time and space,specimen only deforms along radial.Finally,the advantage of this whole-surface deformation measurement in analyzing deformation localization for triaxial tests is discussed through results obtained from drained triaxial tests on saturated sand.更多还原