Dissertation > Industrial Technology > Building Science > Soil mechanics,foundation engineering > Rock ( rock ) mechanics and rock testing > Rock mechanical properties and stress theory

Rock mechanical properties and their fractal dimension of acoustic emission Relations

Author HeHaoYu
Tutor ZhangGuang
School Wuhan University of Technology
Course Mining engineering
Keywords Acoustic emission Uniaxial compression Modulus b-value Fractal
Type Master's thesis
Year 2011
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Acoustic emission technique is to study the mechanical properties of rock an acoustic methods. Through the rock acoustic emission signal analysis and research, infer the nature of change within the rock, the rock failure mechanism inversion. Analysis and Discussion with rock burst tendency of rock in the course of external loads by acoustic emission rules help to understand the dynamics of rock burst tendency to rock instability process and characteristics. In order to systematically study the rock by external loads on the acoustic emission activity patterns, selected marble, granite and sandstone rocks three typical uniaxial compression experiments and collect acoustic emission signals simultaneously to obtain the stress - strain curves acoustic emission characteristic curve of rock acoustic emission during fracture fractal dimension calculation, comprehensive comparative analysis of these three characteristics of rock acoustic emission curve, exploring the evolution of rock characteristics of micro-cracks, and to study the elastic modulus of the rock, rock burst proneness and its relationship between the acoustic emission characteristics. In this paper, marble, granite and sandstone rock mechanical properties of three kinds of research, through the fractal method of rock under pressure to study the acoustic emission signals. Mainly to do the following tasks: (a) taken for marble, granite and sandstone samples, specimens were prepared by a circular uniaxial compression test; calculated under uniaxial compression loading conditions, three kinds of two kinds of rock impact energy indicators, the elastic strain energy index, uniaxial compressive strength, modulus of elasticity and dynamic failure time and other judgments rock burst tendency indicators analyzed marble, granite and sandstone rock burst. Draw rock burst proneness: Granite gt; marble gt; sandstone, for the same origin are reflected in the same kind of rock in a very small range of fixed strain to reach peak stress; (2) in the test acoustic emission signals simultaneously collection; compression of the three conditions in both rock acoustic emission event count analysis, combined with the rock burst proneness were analyzed. (3) According to the theoretical analysis shows that the elastic modulus E and AE b-value relationship, and the b-value and fractal dimension D of the relationship shows that the elastic modulus E and fractal dimension D may be a linear relationship between the experimental results show that fractal dimension and the elastic modulus trends approximate synchronization. (4) the correlation dimension of acoustic emission from start to study under uniaxial compression granite, marble and sandstone of the fractal dimension to analyze the variation and differences with each other, and they were investigated the relationship between rock burst proneness, get some conclusions: the case of uniaxial compression, start loading, with the increasing stress, fractal dimension is also increasing. However, the peak stress in the rock before it will be a period of acoustic emission activity \

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