基于图像技术的三轴土样径向变形测量  

Radial Deformation Measurement of Triaxial Soil Samples Based on Image Technology

作　　者：牟春梅[1,2] 杨警 范兰杨 吴浩杰 MU Chun-mei;YANG Jing;FAN Lan-yang;WU Hao-jie(College of Civil Engineering and Architectural, Guilin University of Technology, Guilin 541004, China;Guangxi Key Laboratory in Geotechnical Mechanics and Engineering, Guilin 541004, China)

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

出　　处：《科学技术与工程》2021年第27期11712-11718,共7页Science Technology and Engineering

基　　金：国家自然科学基金(41867039);广西自然科学基金(2020GXNSFAA297247);广西岩土力学与工程重点实验室项目(2015-A-01-03)。

摘　　要：在常规三轴试验中,由于端部约束的影响难以实现对三轴土样变形的准确测量。将图像测量技术运用于土样的不固结不排水三轴试验中,能够有效地克服常规三轴试验的不足,实现非接触式的三轴土样变形测量。通过已知尺寸的圆柱体在压力室内和压力室外的测量,对有机玻璃压力室和压力室内水介质引起的折射问题引入了折射系数进行修正。结果表明:①通过图像测量方法能够有效克服端部约束对土样变形的影响;②折射效应对土样的径向变形的影响比较大,对轴向变形的影响非常小,且折射修正系数为1.205,对折射效应引起的测量误差可以有效地消除或减小,其绝对测量误差为±0.17 mm。图像测量得到三轴土样的偏应力要小于常规测量值,常规测量方法得到的土体强度偏大。In conventional triaxial tests,it is difficult to accurately measure the deformation of triaxial soil samples due to the influence of end constraints.The application of image measurement technology to the unconsolidated and undrained triaxial test of soil samples can effectively overcome the shortcomings of conventional triaxial test and non-contact triaxial soil sample deformation measurement is realized.Through the measurement of a cylinder of known size in the pressure chamber and outside the pressure chamber,the refraction problem caused by the organic glass pressure chamber and the water medium in the pressure chamber was discussed.The results show these as fouows.Image measurement method can effectively overcome the influence of end constraints on soil sample deformation;the refraction effect has a large influence on the radial deformation of the soil sample,but a very small influence on the axial deformation,and the refraction correction coefficient is 1.205.The measurement error caused by the refraction effect can be effectively eliminated or reduced,and the absolute measurement error is±0.17 mm.The deviatoric stress of triaxial soil samples obtained by image measurement is smaller than that obtained by conventional measurement,and the soil strength obtained by conventional measurement method is larger.

关 键 词：数字图像测量 三轴土样 径向变形 折射修正系数 

分 类 号：TU411[建筑科学—岩土工程]