天然带磁圆柱岩石试件压缩过程应力磁强效应研究

发布时间：2019-01-10 14:14

【摘要】：由于地震发生时,震源深埋地下,对地震的孕育、发展和发生规律难以进行直接的探查,造成地需研究工作与灾害预防要求之间存在着很大的差距。了解岩石在应力作用下,其内部的微裂隙的演化、发展的变化过程及规律,对保证工程安全具有重大意义。自然界的岩石都带有一定强度的磁性,当岩石受外力作用时,岩石内部的微裂隙发生变化,岩石周围空间磁场的分布也会发生变化,磁场随岩石裂隙的变化而变化,正是基于这个理论,本试验拟将磁学物理量磁强引入对岩石压缩断裂过程的研究。本试验采用天然带磁圆柱岩石试件作为研究对象,模拟地壳中的岩石在压缩断裂过程中其应力能量从积累到释放的破裂过程,并对震源孕震、发震过程中岩石内部微裂隙的应力变化与磁强的变化之间的关系进行有限条件的模拟研究；同时,考虑到震源至地表之间的空间距离,研究对岩石周围的磁强近距离遥感测试方法,建立岩石断裂-磁强变化理论模型,探索断裂改变磁场的变化机理。本试验利用加载系统和数据采集系统对试件进行轴向加载,并进行实时监测,获得竖向荷载(应力)、竖向位移(应变)、磁强、试验时间等四个物理量,并通过数据处理和分析找到他们之间的对应关系,将岩石力学性质与电磁学基本物理量联系起来,以岩石压缩断裂应力磁强试验研究为基础的地震地磁观测数据分析方法。大量的试验结果表明,在应力上升阶段,即岩石破坏前应力随应变的增加而增加,磁强随应变的增加而减小,应力和磁强大致呈反对称关系；应力下降阶段,即岩石破坏后失去承载力,岩石的磁强发生突变,随后增大或减小都有可能；在岩石即将达到最大应力附近时,磁强的变化速率,也就是磁强随时间变化的斜率发生变化,产生波动的现象这和岩石本身的带磁情况、本身的裂隙情况以及破坏形态有很大的关系。
[Abstract]:When the earthquake occurs, the earthquake source buried deep underground, the preparation, development and occurrence of the earthquake is difficult to directly explore, resulting in a large gap between the ground needs research work and the disaster prevention requirements. It is of great significance to understand the evolution of microcracks and the changing process and law of the development of rock under stress, which is of great significance to ensure the safety of engineering. The natural rock all has the certain intensity magnetism, when the rock is subjected to the external force, the microfissure in the rock will change, the distribution of the magnetic field around the rock will also change, the magnetic field will change with the change of the rock fissure. It is based on this theory that the magnetic physical quantity magnetic intensity is introduced into the study of rock compression fracture process. In this experiment, the natural magnetic cylindrical rock specimen is used as the research object to simulate the process of stress energy from accumulation to release in the process of compression fracture of rock in the crust, and to prepare earthquake for the source. The relationship between stress change and magnetic intensity variation in rock is simulated under finite conditions. At the same time, considering the spatial distance between the earthquake source and the surface, the paper studies the method of measuring the magnetic intensity near the rock by remote sensing, establishes the theoretical model of the variation of the rock fracture and magnetic intensity, and explores the mechanism of the change of the magnetic field of the fault. In this experiment, the axial loading system and data acquisition system are used to carry out axial loading and real-time monitoring to obtain four physical quantities: vertical load (stress), vertical displacement (strain), magnetic intensity, test time, etc. The corresponding relationship between them is found through data processing and analysis, and the analysis method of seismic geomagnetic observation data based on the experimental study of stress and magnetic intensity of rock compression fracture is presented, which relates the mechanical properties of rock to the basic physical quantity of electromagnetism. A large number of experimental results show that the stress increases with the increase of strain, and the magnetic intensity decreases with the increase of strain at the stage of stress rise, and the stress and magnetic intensity are approximately antisymmetric. At the stage of stress decreasing, that is, the bearing capacity of rock is lost after failure, the magnetic intensity of rock changes suddenly, and then increases or decreases. When the rock is about to reach the maximum stress, the rate of change of the magnetic intensity, that is, the slope of the change of the magnetic intensity with time, will change, and the phenomenon of the fluctuation will occur, and the magnetic condition of the rock itself. There is a great relationship between the fracture and the failure form.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU45

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