不同加载方式下岩石断裂面形貌的多尺度分析

发布时间：2019-03-13 08:30

【摘要】：为了实现从岩石断裂结构面的形貌特征来反推岩石形变和断裂的力学行为和力学机理,本论文研究了岩石在不同加载方式下岩石断裂结构面的形貌特征差异。本论文均采用岩石力学试验中的典型试验—巴西劈裂试验,分别对直径为112mm,厚度为28mm、直径为50mm,厚度为20mm的花岗岩巴西圆盘以及直径为50mm,厚度为25mm的大理岩和砂岩巴西圆盘进行巴西劈裂试验。首先,由MTS (Mechanics Testing Systems)机分别对巴西圆盘试件进行不同速率的加载至断裂失稳；其次,先由MTS机将圆盘加载至断裂强度阈值的1/2、2/3、3/4大小,再将圆盘沿圆盘所在的平面绕中心顺时针旋转30°或45。角(自定义为：预加载转角30°或45。),继而加载至断裂失稳。最后,自定义了岩石断裂面上中心剖线的法向量的方向角和偏态系数的概念,以及对所采集的数据,利用几种先进的数学模型,如数理统计、小波分析和分形理论,进行分析和研究,从而得出如下结论： 1)花岗岩试件中心剖线上法向量的角度分布具有明显的尺度效应,即随着测量尺度的增大,法向量的方向角数据样本的分布越来越接近于正态分布； 2)花岗岩试件中心剖线的偏态系数也具有明显的尺度效应,当测量尺度越小时,其偏态系数越大,说明中心剖线的粗糙度越偏离自定义的标准粗糙度。再者,偏态系数的改变对静载范围内加载速率变化的敏感性并不明显,说明数理统计方法在检测岩石断裂面粗糙度的变化对静载范围内速率改变的敏感性方面,效果并不十分明显； 3)由小波分析中的模极大法自定义能量算法和信噪比,研究发现自定义能量、信噪比和分形变差法均能表现出对试件的预加载转角的差异性,即未转角试件的能量和信噪比分别大于预加载转角试件的能量和信噪比,而未转角试件的分形变差却小于预加载转角试件的分形变差,但在对加载速率的敏感性方面,分形变差法显得比模极大法更为明显,即在静载范围内,加载速率越大,岩石断裂面的分形变差越大； 4)试件在预加载转角前所受的平均断裂阈值的1/2、2/3、3/4的载荷,致使圆盘试件内部造成了一定程度的损伤,并产生一定量的微裂隙。这一结论基本否定了先前部分研究人员所认定的结果,即岩石只有在断裂破坏失稳的瞬间才受到严重损伤而进发出大量能量； 5)在同一加载方式下,大理岩的分形变差大于砂岩的分形变差,表明大理岩断面的粗糙程度较砂岩的更大,并且大理岩断面的粗糙度变化对预加载角度改变的敏感性比砂岩更为明显,即改变同样的预加载角度,大理岩分形变差的变化程度比砂岩分形变差的变化程度更大； 6)从纯数学角度,进行了分形插值函数模型的研究,揭示了分形插值函数的分数阶积分是闭域上的连续函数以及分形插值函数的分数阶积分仍然是分形插值函数的事实。为在后继研究中,试图将分形插值函数的分数阶微积分应用于岩石断裂面的形貌研究打下坚实的理论基础,并尽可能发现其实际应用背景。
[Abstract]:In order to reverse the mechanical behavior and the mechanical mechanism of the rock deformation and fracture from the characteristics of the surface of the rock fracture, this paper studies the difference of the morphology of the rock fracture surface under different loading conditions. In this paper, a typical experiment in rock mechanics test is used to test the Brazilian split test for the Brazilian disc with a diameter of 112 mm, a thickness of 28 mm, a diameter of 50 mm, a thickness of 20 mm, and a marble and sandstone Brazilian disc with a diameter of 50 mm and a thickness of 25 mm. First, the MTS (tics Testing Systems) machine is used to load the different rates of the Brazilian disc test pieces to the fracture instability respectively; secondly, the disc is loaded to the 1/2,2/3,3/4 of the breaking strength threshold by the MTS machine, and then the disc is rotated by 30 degrees or 45 clockwise about the plane where the disc is located. Angle (defined as: pre-load angle of 30 掳 or 45) ), which in turn is loaded to the fracture instability. Finally, the concept of the direction angle and the bias coefficient of the method vector of the central section line on the fracture surface of the rock is defined, and several advanced mathematical models, such as mathematical statistics, wavelet analysis and fractal theory, are used to analyze and study the collected data, so as to obtain the following conclusion: 1) The angular distribution of the method vector on the center of the center of the granite test piece has the obvious scale effect, that is, with the increase of the measurement scale, the distribution of the data samples in the direction of the method vector is more and more close to the normal point. 2) The deviation coefficient of the center section line of the granite test piece also has obvious scale effect. When the measurement scale is small, the larger the deviation coefficient, the more the roughness of the center section line deviates from the customized standard. Moreover, the sensitivity of the change of the bias coefficient to the change of the loading rate in the static load range is not obvious, and the effect of the mathematical statistics method in the detection of the change of the roughness of the rock fracture surface to the rate change of the static load range is not obvious. 3) The energy algorithm and the signal-to-noise ratio are defined by the method in the wavelet analysis. The study shows that the self-defined energy, the signal-to-noise ratio and the differential deformation method can show the pre-loading of the test piece. The difference of the angle is that the energy and the signal-to-noise ratio of the non-rotating test piece are larger than the energy and the signal-to-noise ratio of the pre-loaded corner test piece respectively, while the differential deformation difference of the non-corner test piece is smaller than that of the pre-loaded corner test piece, but the deformation difference method is more than the modulus in terms of the sensitivity to the loading rate. The method is more obvious, that is, in the static load range, the larger the loading rate, the score of the fracture surface of the rock the larger the deformation difference;4) the load of 1/2,2/3,3/4 of the average fracture threshold value of the test piece at the pre-loading angle, causing a certain degree of damage to the inside of the disc test piece, and generating The conclusion is that the rock can only be seriously damaged at the moment of failure and failure of the rock. A large amount of energy is sent;5) in the same loading mode, the deformation of the marble is poor. The difference of the deformation of the sandstone is larger than that of the sandstone, which indicates that the roughness of the section of the marble is larger than that of the sandstone, and the sensitivity of the change of the roughness of the marble section to the change of the pre-loading angle is more obvious than that of the sandstone, that is, the change In the same pre-loading angle, the variation of the differential deformation of the marble is lower than that of the sandstone. A greater degree of variation;6) from a pure mathematical point of view. The study of the fractal interpolation function model reveals that the fractional order integral of the fractal interpolation function is a continuous function on the closed domain and the fractional order integral of the fractal interpolation function In the follow-up study, the fractional-order calculus of the fractal interpolation function is used to lay a solid theoretical foundation for the study of the morphology of the fracture surface of the rock.
【学位授予单位】：江苏大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU45

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