本文選題：聲發(fā)射 + 定位精度�。� 參考：《重慶大學(xué)》2015年碩士論文

【摘要】：對于脆性巖石而言,巖石的破壞過程與其內(nèi)部微裂紋演化過程是一致的,微裂紋的產(chǎn)生與擴展,伴隨著彈性波的釋放并在巖石內(nèi)快速傳播,即聲發(fā)射。聲發(fā)射信號一般較弱,需要借助于專門的儀器加以監(jiān)測,利用多個聲發(fā)射換能器可以實現(xiàn)聲發(fā)射位置的定位。但是由于聲發(fā)射信號的復(fù)雜性和非平穩(wěn)性特性,以及巖石試件的形狀、尺寸、孔隙度等物理特性的影響,聲發(fā)射定位的精度較差,因而使得聲發(fā)射技術(shù)的研究和應(yīng)用受到了很大限制。本文借助于實驗室測試分析的方法,研究聲發(fā)射定位精度的重要影響因素,對于更精確的反演聲發(fā)射源的信息具有重要的理論意義和實際應(yīng)用價值。本文運用斷鉛試驗方法通過研究不同試驗條件下聲發(fā)射三維定位的準(zhǔn)確度,并對其產(chǎn)生的誤差進行分析,在獲取大量聲發(fā)射定位試驗數(shù)據(jù)的基礎(chǔ)上,對影響聲發(fā)射定位精度的各因素進行理論分析及處理,得到更為精確的聲發(fā)射源定位信息,提高聲發(fā)射定位的有效性。主要研究成果有:①利用PCI-2型聲發(fā)射測試系統(tǒng),開展不同試件尺寸條件下的砂巖聲發(fā)射斷鉛定位試驗,探討試件尺寸對定位精度的影響大小,分析試件尺寸與定位誤差間的線性規(guī)律。②開展換能器距巖石試件邊界不同距離條件下的砂巖聲發(fā)射斷鉛定位試驗,探討邊界效應(yīng)對聲發(fā)射定位精度的影響,并結(jié)合試件尺寸研究,探討不同試件尺寸條件下?lián)Q能器距巖石試件邊界的最優(yōu)距離。③開展不同換能器耦合耦合劑條件下的砂巖聲發(fā)射斷鉛定位試驗,對比分析不同耦合劑對砂巖定位精度的影響,尋找最適宜的耦合劑以提高聲發(fā)射定位精度。④開展不同墊板厚度條件下的砂巖聲發(fā)射斷鉛定位試驗,探討換能器與砂巖試件間的墊板厚度對聲發(fā)射定位精度的影響規(guī)律,分析聲發(fā)射換能器與砂巖試件之間墊板的合理厚度。
[Abstract]:For brittle rocks, the failure process of rocks is consistent with the evolution process of microcracks in rocks. The generation and propagation of microcracks are accompanied by the release of elastic waves and rapid propagation in rocks, i.e. acoustic emission. Acoustic emission signals are usually weak and need to be monitored by means of special instruments. The location of acoustic emission can be realized by using multiple acoustic emission transducers. However, because of the complexity and non-stationary characteristics of acoustic emission signal and the influence of physical characteristics such as shape, size and porosity of rock specimen, the accuracy of acoustic emission localization is poor. Therefore, the research and application of acoustic emission technology are greatly restricted. With the help of the method of laboratory test and analysis, this paper studies the important factors that affect the accuracy of acoustic emission location, which has important theoretical significance and practical application value for more accurate retrieval of acoustic emission source information. In this paper, the accuracy of three dimensional acoustic emission localization under different experimental conditions is studied by using lead broken test method, and the errors generated are analyzed. On the basis of obtaining a large number of acoustic emission localization test data, a large number of acoustic emission localization test data are obtained. The factors affecting the accuracy of acoustic emission positioning are analyzed and processed theoretically to obtain more accurate localization information of acoustic emission sources and to improve the effectiveness of acoustic emission positioning. The main research results are as follows: using PCI-2 acoustic emission testing system, the main research results are as follows: (1) using PCI-2 model acoustic emission testing system, the lead broken location test of sandstone acoustic emission under different specimen sizes is carried out, and the influence of specimen size on positioning accuracy is discussed. The linear rule between specimen size and positioning error is analyzed. 2. The acoustic emission lead broken location test of sandstone under different distances from the transducer to the rock specimen boundary is carried out, and the influence of boundary effect on the accuracy of acoustic emission location is discussed. Based on the study of specimen size, the optimum distance between transducer and rock specimen boundary is discussed. 3. The acoustic emission lead broken location test of sandstone under different coupling agent conditions is carried out. By comparing and analyzing the influence of different coupling agents on the positioning accuracy of sandstone, the most suitable coupling agent is found to improve the positioning accuracy of acoustic emission. 4. The lead broken location test of sandstone acoustic emission under different thickness of gasket is carried out. The influence of the thickness of the gasket between the transducer and the sandstone specimen on the accuracy of acoustic emission positioning is discussed, and the reasonable thickness of the gasket between the acoustic emission transducer and the sandstone specimen is analyzed.
【學(xué)位授予單位】：重慶大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TU45

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本文編號：1881809