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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;④DSCM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。
Digital image correlation and correlation coefficient calculation are the basic principles and basic algorithms of digital speckle correlation method (DSCM). However, before and after the occurrence of fractures, the rock mass can lead to the obvious change of the digital image correlation in the fracture area and the result of the correlation coefficient calculation Therefore, the conventional method of constructing image-related analysis pixel blocks with point as the center inevitably leads to large errors and even errors. Therefore, based on the analysis of the distribution characteristics of rock fissures and their simplified types, a simple and effective new method - “one and a half” method is proposed to eliminate the influence of fissures. It is implemented in the PhotoInfor software system developed by ourselves This function was applied and applied to the deformation and rupture process of a double-hole rock specimen under uniaxial compression. The results show that: ① “One-and-five” method effectively solves the accuracy problem of DSCM with dynamic fractured rock mass and consolidates the dominance of digital photogrammetry in fine field observation of rock-burst evolution; ② “One-and-five” method can also be used as a DSCM universal precision improvement algorithm in the deformation measurement of materials with both dynamic and non-dynamic fractures. ③ In the uniaxial compression of the rock, DSCM obtained the rock The relationship between deformation process and axial stress was found. It was found that the rock mass began to appear locally larger shear strain near the peak value, but the serious damage of rock mass structure occurred near the residual stress phase. ④DSCM can reveal the interior of the rock mass The relationship between the structure rupture and the deformation around the hole, so as to provide an effective way to further study the method of predicting the internal variation of the surrounding rock through the displacement of the hole wall.