本文選題：原生結(jié)構(gòu)煤 + 超聲��； 參考：《河南理工大學(xué)》2016年碩士論文

【摘要】：地球物理勘探技術(shù)是煤礦安全和煤層氣開發(fā)的保障,開展加載條件下煤的超聲實(shí)驗(yàn)為利用聲波測井技術(shù)測定煤巖結(jié)構(gòu)和物質(zhì)組成提供理論和實(shí)驗(yàn)基礎(chǔ)。本論文以研究原生結(jié)構(gòu)煤在加載條件下的超聲波-應(yīng)變響應(yīng)特征為目的,通過對平煤八礦不同變質(zhì)程度、不同割理方向的煤樣進(jìn)行常溫單軸加載條件下的超聲波-應(yīng)變測試實(shí)驗(yàn),分析其彈性、應(yīng)變響應(yīng)差異。研究表明:(1)在應(yīng)力未加載時,三種煤樣的縱橫波速度以及衰減系數(shù)都存在差異性,一般情況下平行層理的兩個方向和垂直層理的方向相差較大,且存在垂直層理的方向縱橫波速最小,衰減系數(shù)值較小,說明垂直層理方向煤樣中超聲波衰減的最厲害。這與沿Z方向煤樣的壓實(shí)效應(yīng)最大有關(guān)。(2)在加載狀態(tài)下,Qs普遍比Qp大,說明實(shí)際煤層對縱波的吸收衰減作用大于橫波。在煤層某些參數(shù)測試方面,選擇橫波作為檢測波更有優(yōu)勢。煤樣衰減各向異性系數(shù)大于速度各向異性系數(shù),這也說明了品質(zhì)因子Q可能是一個比速度對煤樣各向異性更為敏感的參數(shù)。(3)兩種焦煤隨著應(yīng)力的增加,平行層理的兩個方向的縱橫波速和衰減各向異性變化趨勢都不盡相同,一般情況下Y方向縱橫波速和衰減的各向異性系數(shù)都大于X方向。這也間接說明了煤層中裂隙的走向變異程度具有差異性。(4)加載過程中,煤樣的V_p隨著應(yīng)力的升高而逐漸增加,但在低應(yīng)力段的增長幅度要高于高應(yīng)力區(qū)段。在0-2MPa低應(yīng)力區(qū)間時,V_p的增大幅度較快,當(dāng)應(yīng)力高于2MPa時,V_p的增長幅度也開始變慢。針對三種煤樣的V_S而言,其變化趨勢和V_p類似,低應(yīng)力區(qū)波速增長幅度較大,到達(dá)V_S最大值后迅速下降。此外,三種煤樣抗壓強(qiáng)度存在差異,同種變質(zhì)程度煤樣三個方向上也存在差異。V_S最大值點(diǎn)不同變質(zhì)程度煤樣出現(xiàn)在不同應(yīng)力加載處。(5)對于加載狀態(tài)下三種變質(zhì)程度煤樣來說,體積模量變化從整體上來說都是先增加后到達(dá)某個最大點(diǎn)或者時穩(wěn)定在一段時間后下降,這個過程包含了煤樣中孔隙的閉合、張開和發(fā)育等階段;針對某種特定變質(zhì)程度的煤樣來說,在加載狀態(tài)下,三種煤樣的體積模量也是隨著加載應(yīng)力的增加而增大,但是三個方向上體積模量的增加快慢存在差異。一般情況下都是平行層理的兩個方向的體積模量大于垂直層理方向。通過對單軸應(yīng)力作用下同一礦區(qū)不同變質(zhì)程度、不同割理方向的原生結(jié)構(gòu)煤的超聲波-應(yīng)變響應(yīng)特征進(jìn)行分析,探索了同一礦區(qū)煤巖在宏觀和微觀物質(zhì)組成、結(jié)構(gòu)及構(gòu)造在彈性特征和應(yīng)變方面的差異,為今后運(yùn)用地震勘探探測煤層物性、結(jié)構(gòu)及軟分層的分布提供理論及實(shí)驗(yàn)基礎(chǔ)。
[Abstract]:Geophysical exploration technology is the guarantee of coal mine safety and coalbed methane development. The ultrasonic experiment of coal under loading condition provides a theoretical and experimental basis for the determination of coal structure and material composition by using acoustic logging technology. In order to study the ultrasonic and strain response characteristics of primary structure coal under loading conditions, the metamorphic degree of the coal under different metamorphic degrees is studied in this paper. The ultrasonic and strain tests of coal samples with different cleavage directions under uniaxial loading at room temperature were carried out to analyze the difference in elasticity and strain response. The results show that the longitudinal and shear wave velocities and attenuation coefficients of the three kinds of coal samples are different when the stress is not loaded. In general, the two directions of parallel bedding and the direction of vertical bedding are quite different. The longitudinal and transverse wave velocity in the direction of vertical bedding is the smallest and the attenuation coefficient is small, which indicates that the ultrasonic wave attenuation is the most severe in the coal samples in the vertical stratification direction. This is related to the maximum compaction effect of coal samples along Z direction. 2) under loading condition, Qs is generally larger than QP, indicating that the absorption and attenuation of longitudinal wave in actual coal seam is greater than that in S-wave. In some coal seam parameters test, it is more advantageous to select the shear wave as the detection wave. The attenuation anisotropy coefficient of coal sample is larger than that of velocity anisotropy coefficient, which indicates that the quality factor Q is a more sensitive parameter than velocity to the anisotropy of coal sample. The variation trends of longitudinal and transverse wave velocities and attenuation anisotropy in two directions of parallel layer are different. In general, the anisotropy coefficients of Y direction longitudinal and transverse wave velocity and attenuation are larger than X direction. This also indirectly shows that during the loading process, the VSP of coal samples increases with the increase of stress, but the increase of VSP in the low stress section is higher than that in the high stress zone. When the stress of 0-2MPa is higher than that of 2MPa, the increase of VSP increases rapidly, and the increase of VSP becomes slower when the stress is higher than that of 2MPa. For the three kinds of coal samples, the variation trend is similar to that of V\ +\ {\}\ In addition, the compressive strength of the three kinds of coal samples is different, and there are also differences in three directions of the same metamorphic coal samples. The maximum value of V _ S and different metamorphic coal samples appear at different stress loading sites. (5) for the three kinds of metamorphic coal samples under loading state, the three metamorphic coal samples have different degrees of metamorphism. As a whole, the volume modulus changes are first increased and then reached a certain maximum point, or stable after a period of time, which includes the stages of pore closure, opening and development in coal samples. For a coal sample with a specific metamorphic degree, the bulk modulus of the three coal samples increases with the increase of the loading stress under the loading condition, but the increase rate of the bulk modulus in the three directions is different. In general, the volume modulus in two directions of parallel bedding is larger than that in vertical direction. By analyzing the ultrasonic strain response characteristics of primary structural coal with different metamorphism degree and different cleat direction under uniaxial stress, the macroscopic and microscopic composition of coal and rock in the same mining area is explored. The differences in elastic characteristics and strain between structures and structures provide a theoretical and experimental basis for the future application of seismic exploration to detect the distribution of coal bed physical properties, structure and soft stratification.
【學(xué)位授予單位】：河南理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：TD315

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