基于智能手机和数字图像相关的模型实验变形场测量标点法

为提高模型实验位移测量精度和效率,通过智能手机作为图像采集工具,结合数字图像相关技术获取不同载荷状态下附着于被测体表面标点的位移。基于标点法的基本原理引入刚体运动补偿法进行误差校正以提高测量精度,同时通过实验验证了标点法的可靠性。将标点法应用于相似材料模型实验变形场量测中,在模型表面设置自行研制的数字图像相关技术(digital image correlation, DIC)和全站仪两用标点,利用标点法获取岩层位移,并使用全站仪和百分表同步量测,验证其有效性。结果表明:通过刚体运动补偿法进行误差校正,标点法具有与商业测试系统相当的精度;标点法所测得岩层变化均与实际情况一致,该方法测量结果与百分表的测量结果最大相对偏差为6.1%,与全站仪最大相对偏差为5.7%,满足模型实验测量的精度要求。研究成果为进一步研究覆岩变形和动态沉陷规律提供了新的监测手段。

Application of Measuring Deformation Method Using Target Markers in Physical Model Test Based on Smart Phone and DIC

In order to improve the precision and efficiency of displacement measurement in model experiment, smart phone is used as an image acquisition tool to obtain the displacement attached to the surface of the measured body under different loading conditions combined with digital image related technology. Based on the basic principle of punctuation, a rigid body motion compensation method is introduced to improve the accuracy of measurement. The punctuation method is applied to the deformation field measurement of similar material model experiment. The DIC and total station punctuation marks developed by ourselves are set on the model surface. The rock displacement is obtained by using the punctuation method, and the total station and dial indicator are used for synchronous measurement to verify its effectiveness. The results show that the accuracy of punctuation method is comparable to that of commercial test system. The variation of rock strata measured by punctuation method is consistent with the actual situation. The maximum relative deviation between the measured results of this method and that of the dial indicator is 6.1%, and that of the total station is 5.7%, which meets the accuracy requirements of the model experiment. The results provide a new monitoring method for further studying the deformation and dynamic subsidence of overburden.