【摘要】：在外力作用下僅產(chǎn)生很小的變形就發(fā)生破壞斷裂的材料稱為脆性材料,如巖石等。脆性材料受力達到一定程度時會突然發(fā)生破壞,這種突發(fā)的、沒有預(yù)兆的破壞將會給工程帶來嚴(yán)重的災(zāi)害,因此利用聲發(fā)射技術(shù)對脆性材料損傷進行實時監(jiān)測,研究其內(nèi)部損傷破壞過程具有重要意義。巖體的穩(wěn)定性受水分的影響很大,巖石受水浸濕后使巖石力學(xué)性質(zhì)受到影響,導(dǎo)致巖石強度降低,塑性變形成份增加。含水巖石與干燥巖石的聲發(fā)射規(guī)律有很大不同。同一試樣飽和狀態(tài)下的聲發(fā)射特征和干燥狀態(tài)下的聲發(fā)射特征有較大差異,而且這種差異隨著含水率的變化而變化。本文通過巖石的單軸壓縮聲發(fā)射試驗,利用小波變換的方法對不同飽和度巖石的聲發(fā)射信號進行處理,并用聲發(fā)射參數(shù)的方法研究巖石的損傷表征。(1)根據(jù)小波變換的理論,研究利用小波變換對聲發(fā)射信號的不同頻帶能量提取的方法；利用這種方法對不同飽和度的完整砂巖和有初始損傷砂巖的單軸壓縮試驗的聲發(fā)射信號進行處理,提取各頻帶的信號的能量,通過分析各頻帶的能量得到能夠表明聲發(fā)射信號能量分布規(guī)律的特征頻帶和其聲發(fā)射信號的主頻帶,并得到其聲發(fā)射信號頻帶能量的分布規(guī)律。(2)對閃長巖單軸壓縮的聲發(fā)射試驗的數(shù)據(jù)進行分析。首先分析閃長巖的聲發(fā)射信號的特性：根據(jù)聲發(fā)射信號的活動情況反映巖石整個破壞過程的損傷情況,分析損傷初期、損傷演化和失穩(wěn)破壞各階段的聲發(fā)射信號的活動情況。其次利用小波變換的方法對閃長巖聲發(fā)射信號進行處理,得到閃長巖的聲發(fā)射信號能量主要分布頻帶。最后根據(jù)巖石損傷變量與應(yīng)變和聲發(fā)射參數(shù)的定量關(guān)系式,利用閃長巖聲發(fā)射的相對能量累積計數(shù)與相應(yīng)的應(yīng)變的數(shù)據(jù),通過MATLAB擬合得出閃長巖損傷變量D的公式以及其損傷的應(yīng)力應(yīng)變關(guān)系式,理論的損傷應(yīng)力應(yīng)變曲線與試驗應(yīng)力應(yīng)變曲線比較吻合,驗證了閃長巖損傷變量公式的準(zhǔn)確性。
[Abstract]:Materials with small deformation and fracture under external force are called brittle materials, such as rocks and so on. When the force of brittle material reaches a certain degree, the damage of brittle material will suddenly occur. This kind of sudden and unforeseen damage will bring serious disaster to the project, so the acoustic emission technology is used to monitor the damage of brittle material in real time. It is of great significance to study the internal damage and failure process. The stability of rock mass is greatly affected by moisture. After the rock is soaked with water, the mechanical properties of rock are affected, which leads to the decrease of rock strength and the increase of plastic deformation composition. The acoustic emission law of water-bearing rock is very different from that of dry rock. The acoustic emission characteristics of the same sample in saturated state are quite different from those in dry state, and the difference varies with the change of moisture content. In this paper, the acoustic emission signals of rocks with different saturation are processed by wavelet transform through the uniaxial compression acoustic emission test of rocks. The damage characterization of rock is studied by the method of acoustic emission parameters. (1) according to the theory of wavelet transform, the method of extracting energy from different frequency bands of acoustic emission signal by wavelet transform is studied. The acoustic emission signals of complete sandstone with different saturation and uniaxial compression test with initial damage sandstone are processed by this method, and the energy of the signal in each frequency band is extracted. By analyzing the energy of each frequency band, the characteristic frequency band which can show the energy distribution law of acoustic emission signal and the main frequency band of its acoustic emission signal are obtained. The distribution of band energy of acoustic emission signal is obtained. (2) the data of acoustic emission test of diorite uniaxial compression are analyzed. Firstly, the characteristics of acoustic emission signal of diorite are analyzed: according to the activity of acoustic emission signal, the damage of rock in the whole failure process is reflected, and the activity of acoustic emission signal in each stage of damage evolution and instability is analyzed. Secondly, the acoustic emission signal of diorite is processed by wavelet transform, and the main energy distribution band of acoustic emission signal of diorite is obtained. Finally, according to the quantitative relationship between rock damage variables and strain and acoustic emission parameters, the relative energy accumulation count and the corresponding strain data of diorite acoustic emission are used. The formula of diorite damage variable D and its damage stress-strain relationship are obtained by MATLAB fitting. The theoretical damage stress-strain curve is in good agreement with the experimental stress-strain curve, which verifies the accuracy of the damage variable formula of diorite.
【學(xué)位授予單位】：東北大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TU45

【參考文獻】

相關(guān)期刊論文 前2條

1 殷有泉;巖石的塑性、損傷及其本構(gòu)表述[J];地質(zhì)科學(xué);1995年01期

2 周維垣;楊延毅;;節(jié)理巖體的損傷斷裂模型及驗證[J];巖石力學(xué)與工程學(xué)報;1991年01期

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本文編號：2476378