本文關(guān)鍵詞： 雙面剪切 單面剪切 聲發(fā)射 表面形貌　出處：《太原理工大學》2017年碩士論文　論文類型：學位論文

【摘要】：巖石是一種由多種礦物質(zhì)組成的非均質(zhì)體,所以巖石的性質(zhì)比較復雜。在自然界以及工程中,巖石的受力狀態(tài)十分復雜,所以研究巖石的破壞規(guī)律具有一定的困難。巖體失穩(wěn)破壞的主要形式之一是剪切破壞,包括單面剪切和雙面剪切。巖石在不同應力狀態(tài)下的破裂規(guī)律具有很大的差別,所以研究巖石在不同應力狀態(tài)下的破裂特征有重大意義。鑒于以上分析,本文進行了不同應力條件下花崗巖的單面剪切和雙面剪切破壞特性的試驗研究,比較不同應力狀態(tài)下剪應力-位移曲線中各個階段的特點,同時結(jié)合聲發(fā)射技術(shù),進一步探討巖石破壞過程中各個階段的聲發(fā)射特征,并借助3D激光掃描儀掃描剪切面的表面形貌,以更好的把握巖石破裂規(guī)律。通過研究發(fā)現(xiàn):(1)花崗巖單面剪切和低法向應力的雙面剪切破裂全過程中,剪應力-位移曲線大致可以分成4個階段:加載調(diào)整段(OA)、彈性變形段(AB)、彈塑性變形段(BD)、峰后變形段(DE)。但是雙面剪切過程中,當法向應力大于50MPa時,例如70MPa時,花崗巖破裂過程的剪應力-位移曲線多出了一段很長的塑性變形強化段,表現(xiàn)出了很強的塑性。(2)花崗巖單面剪切破壞過程中,隨著法向應力的增加,巖樣的峰值抗剪強度、殘余抗剪強度、彈性變形段斜率以及峰值強度與殘余強度之比都逐漸增加,花崗巖的單面剪切摩擦系數(shù)逐漸減小。(3)花崗巖雙面剪切破壞過程中,隨著法向應力的增加,巖樣的峰值抗剪強度和殘余抗剪強度逐漸增加,彈性變形段斜率和峰值強度與殘余強度之比逐漸減小,雙面剪切摩擦系數(shù)先增大再減小。(4)在花崗巖單面剪切過程中,隨著法向應力的增加,當剪應力達到花崗巖的峰值抗剪強度時,聲發(fā)射計數(shù)和能量先增大后減小,聲發(fā)射計數(shù)累計和能量累計逐漸減小。(5)在花崗巖雙面剪切過程中,隨著法向應力的增加,當剪應力達到花崗巖的峰值抗剪強度時,聲發(fā)射計數(shù)、能量和能量累計逐漸增大,聲發(fā)射計數(shù)累計先減小后增大。(6)花崗巖單面剪切和雙面剪切破壞后,隨著法向應力的增加,(?)的值逐漸減小。說明法向應力越大,剪切面凹凸不平度越小。
[Abstract]:Rock is a heterogeneous body composed of a variety of minerals, so the properties of rock are complex. In nature and engineering, the stress state of rock is very complicated. Therefore, it is difficult to study the failure law of rock mass. One of the main forms of rock failure is shear failure, including one-sided shear and two-sided shear. The fracture law of rock under different stress states is very different. Therefore, it is of great significance to study the fracture characteristics of rocks under different stress states. In view of the above analysis, this paper has carried out an experimental study on the single and double shear failure characteristics of granite under different stress conditions. The characteristics of each stage in the shear stress-displacement curve under different stress states are compared. At the same time, combined with acoustic emission technology, the acoustic emission characteristics of each stage in the rock failure process are further discussed. With the help of 3D laser scanner, the surface morphology of the shear plane is scanned to better understand the rule of rock fracture. It is found that during the whole process of one-sided shear and low-normal stress two-sided shear fracture of the granite, The shear stress-displacement curve can be roughly divided into four stages: load adjustment section, elastic deformation section, elastic deformation section, elastic-plastic deformation section, and post-peak deformation section, but in the double-sided shear process, when the normal stress is greater than 50 MPA, for example, 70 MPA, In the shear stress-displacement curve of granite fracture process, there is a long plastic deformation strengthening section, which shows a very strong plastic deformation strengthening section.) in the process of single face shear failure of granite, the peak shear strength of rock sample increases with the increase of normal stress. The residual shear strength, the slope of elastic deformation section and the ratio of peak strength to residual strength increase gradually, and the friction coefficient of one-sided shear of granite decreases gradually. The peak shear strength and residual shear strength of rock samples increase gradually, and the slope and the ratio of peak strength to residual strength of elastic deformation section decrease gradually. With the increase of normal stress, when shear stress reaches the peak shear strength of granite, the AE count and energy increase first and then decrease. With the increase of normal stress, when shear stress reaches the peak shear strength of granite, the acoustic emission count, energy and energy accumulative increase gradually. With the increase of normal stress? It shows that the greater the normal stress, the smaller the roughness of the shear plane.
【學位授予單位】：太原理工大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TU45

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本文編號：1513325