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李元海, 林志斌, 靖洪文, 杨圣奇. 含动态裂隙岩体的高精度数字散斑相关量测方法[J]. 岩土工程学报, 2012, 34(6): 1060-1068.
引用本文: 李元海, 林志斌, 靖洪文, 杨圣奇. 含动态裂隙岩体的高精度数字散斑相关量测方法[J]. 岩土工程学报, 2012, 34(6): 1060-1068.
LI Yuan-hai, LIN Zhi-bin, JING Hong-wen, YANG Sheng-qi. High-accuracy digital speckle correlation method for rock with dynamic fractures[J]. Chinese Journal of Geotechnical Engineering, 2012, 34(6): 1060-1068.
Citation: LI Yuan-hai, LIN Zhi-bin, JING Hong-wen, YANG Sheng-qi. High-accuracy digital speckle correlation method for rock with dynamic fractures[J]. Chinese Journal of Geotechnical Engineering, 2012, 34(6): 1060-1068.

含动态裂隙岩体的高精度数字散斑相关量测方法

High-accuracy digital speckle correlation method for rock with dynamic fractures

  • 摘要: 数字图像相关与相关系数计算是数字散斑相关方法( DSCM )的基本原理与基础算法,然而,岩体在产生裂隙前后,会导致裂隙区数字图像相关性的明显改变和依据相关系数计算结果的错误判断,因此,常规以点为中心来构建图像相关分析像素块的方法必然会产生较大误差甚至错误。为此,基于岩体裂隙的分布特征及其简化型式的分析,提出一种简单有效的新方法——“一点五块”法以消除裂隙影响,在自行研制的 PhotoInfor 软件系统中实现了这一功能,并针对一含双孔岩石试件单轴压缩下的变形与破裂过程进行了应用研究。结果表明:①“一点五块”法有效解决了含有动态裂隙岩体的 DSCM 量测的精度问题,巩固了数字照相量测技术在岩石破裂演变全场精细观测实验中的优势地位;② “ 一点五块 ” 法同时可作为一种 DSCM 通用精度提高算法,应用于包含动态裂隙与非动态裂隙的材料变形量测中;③在岩石单轴压缩过程中, DSCM 获得了岩体变形破裂演变过程与轴向应力之间的关系,发现了岩体在峰值附近开始出现局部较大剪应变,但岩体结构的严重破坏则发生在接近残余应力阶段;④ DSCM 能够揭示岩体内部结构破裂情况与孔洞周围变形之间的时间关系,从而为进一步研究通过孔洞洞壁的位移来预测围岩内部变化的方法提供一个有效的手段。

     

    Abstract: The digital image correlation and the calculation of correlation coefficient are the basic principle and the key algorithm of the digital speckle correlation method (DSCM). The image block correlation near the fracture zone will change much before and after the occurrence of cracks in the rock specimen. So the common image block construction method using the measured pixel point as the centre of image block will cause many errors. In order to solve the problem, a simple and efficient method named OP & FB (One pixel point and five pixels block) is put forward to eliminate the fracture impact, whose function has been implemented by coding in the self-developed software package PhotoInfor . The application results in axial compression for rock with two holes show that (1) the OP & FB method can solve the deformation measurement problem and increase the measurement accuracy for the rock with dynamic fractures induced by compression; (2) the OP & FB method can be used as a general high-accuracy method in DSCM for materials with or without dynamic fractures; (3) the relation between the fracture evolution and the axial load of rock specimen during axial compression is obtained, and local big shear strain occurs near the peak load while the critical damage of rock mass structure arises approaching the residual stress stage; and (4) the DSCM with OP & FB method can obtain the relation of the deformation on the wall of hole within the rock specimen and the crack information of surrounding rock mass. So it will provide powerful tools for establishing a forecasting technique for internal rock mass crack by measuring the displacement of the wall of the hole, and it has obvious meaning in the monitoring of tunnel engineering construction.

     

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