三轴试样数字化测量中折射误差校正  

Refraction Error Correction in Digital Measurement of Triaxial Samples

作　　者：范兰杨 牟春梅[1,2] 杨警 吴浩杰 FAN Lanyang;MU Chunmei;YANG Jing;WU Haojie(College of Civil Engineering and Architecture,Guilin University of Technology,Guilin 541004,Guangxi,China;Guangxi Key Laboratory of Geomechanics and Geotechnical Engineering,Guilin University of Technology,Guilin 541004,Guangxi,China)

机构地区：[1]桂林理工大学土木与建筑工程学院,广西桂林541004 [2]桂林理工大学广西岩土力学与工程重点实验室,广西桂林541004

出　　处：《济南大学学报（自然科学版）》2022年第5期571-579,共9页Journal of University of Jinan(Science and Technology)

基　　金：国家自然科学基金项目(41867039);广西自然科学基金项目(2020GXNSFAA297247)。

摘　　要：为了消除压力室壁和密闭介质在三轴数字化测量中的折射放大效应,克服常规三轴试验的缺陷,在压力室表面粘贴人工标记点,追踪标记点在不同加载阶段的坐标变化,获得压力室变形参数,重构压力室数学模型,确定折射界面;基于光线追踪原理,建立三维折射误差校正模型,消除折射误差;以三轴试样空气中的值为真值,对比校正前、后的测量值。结果表明:相比空气中的测量值,压力室注水后,试样的轴向高度放大1.011 4倍,径向长度放大1.219倍;经三维折射误差校正模型校正后,轴向测量值最大误差为0.190 mm,平均误差为0.127 mm,最大径向截面测量误差为0.245 mm,平均误差为0.140 3 mm;三维折射误差校正模型能有效减小测量过程中的折射误差。To eliminate the refraction amplification effect of pressure chamber walls and closed medium in triaxial digital measurement, and overcome defects of conventional triaxial tests, manual mark points were pasted on the surface of a pressure chamber to track coordinate changes of the mark points in different loading stages to obtain deformation parameters of the pressure chamber. A mathematical model of the pressure chamber was reconstructed to determine the refraction interface. Based on ray tracing principle, a three-dimensional refraction error correction model was established to eliminate refraction errors. The value in the air of triaxial samples was taken as the true value to compare the measured values before and after the correction. The results show that compared with the measured value in the air, the axial height of the samples is enlarged by 1.011 4 times, and the radial length is enlarged by 1.219 times after injecting water in the pressure chamber. After correcting by using the three-dimensional refraction error correction model, the maximum error of the axial measured value is 0.190 mm, and the average error is 0.127 mm. The maximum radial section measurement error is 0.245 mm, and the average error is 0.1403 mm. The three-dimensional refraction error correction model can effectively reduce refraction errors in measurement process.

关 键 词：三维折射误差校正模型 光线追踪 数字化测量 折射误差 

分 类 号：TU411[建筑科学—岩土工程]