本文選題：巖石力學　切入點：三軸壓縮　出處：《太原理工大學》2015年碩士論文

【摘要】：隨著工程建筑事業(yè)的迅速發(fā)展，巖石力學問題成為了國內(nèi)外學者研究的熱門學科。但是，巖石力學畢竟還是一門發(fā)展中的學科，并且研究的對象很復雜，因此在巖石工程中還存在著大量工程技術(shù)人員難以解決的難題。 本文是基于對CT圖像的分析處理，獲得粉砂巖試件的一些基本性質(zhì)，結(jié)合損傷力學，對粉砂巖試件的本構(gòu)模型進行研究。本項目屬于國家自然科學基金項目（51104105）。 本文首先介紹本次試驗主要用到的儀器：高精度顯微CT系統(tǒng)、微型三軸壓縮儀器、小型鉆銑機床和金剛石切割機，簡單的描述CT掃描系統(tǒng)與微型煤巖試驗機的結(jié)合使用方法。利用微型煤巖試驗機對三種砂巖試件進行三軸壓縮破壞試驗，并在宏觀上觀察分析不同圍壓下各種巖石試件的破壞結(jié)果。利用微型煤巖試驗機與高精度顯微CT儀器相結(jié)合的方式，獲得大量壓縮破壞過程中巖石試件內(nèi)部變化的顯微CT圖像，并根據(jù)不同壓縮破壞階段的CT圖像對比，分析試件內(nèi)裂隙的發(fā)展情況。根據(jù)CT圖像不同掃描層的平均CT數(shù)的大小，分析巖石試件的整體強度及試件破壞后的強度變化，得出初始巖石密度的不均勻性和壓縮破壞過程中試件損傷破壞的不均勻性。引入了微元體的概念，通過觀察掃描層中試件CT數(shù)大小的分布曲線，認為巖石試件的微元強度服從weibull分布，分析在不同壓縮破壞階段巖石試件微元強度分布的變化，在試件破壞后微元強度分布曲線會向左移動。引入了損傷變量的概念，根據(jù)CT圖片分析巖石試件在壓縮過程中損傷變量的變化，研究了粉砂巖試件的損傷演化規(guī)律。通過CT圖像分析獲得的巖石壓縮中展現(xiàn)的特性，最終還是要建立本構(gòu)模型來表達。結(jié)合損傷統(tǒng)計的方法，將巖石試件的壓縮破壞過程分成了三個階段，分別建立每個階段的本構(gòu)模型。對粉砂巖試件的全應力應變曲線進行比較分析，，認為峰值應力與圍壓存在線性關(guān)系，依此建立不同圍壓下的粉砂巖試件的本構(gòu)模型，并對該模型進行驗證。
[Abstract]:With the rapid development of engineering and construction, rock mechanics has become a hot subject for scholars at home and abroad. However, rock mechanics is still a developing subject, and the object of study is very complex. Therefore, there are still a lot of difficult problems in rock engineering which are difficult to be solved by engineers and technicians. In this paper, based on the analysis and processing of CT images, some basic properties of siltstone specimen are obtained. Combined with damage mechanics, the constitutive model of siltstone specimen is studied. This paper first introduces the main instruments used in this experiment: high precision micro CT system, micro triaxial compression instrument, small drilling and milling machine and diamond cutting machine. A simple description of the combination of CT scanning system and micro coal and rock testing machine is presented. The triaxial compression failure test of three kinds of sandstone specimens is carried out by using the micro coal and rock testing machine. The failure results of various rock specimens under different confining pressures are observed and analyzed macroscopically. The microscopic CT images of the internal changes of rock specimens during compression failure are obtained by means of the combination of micro coal and rock testing machine and high precision micro CT instrument. According to the contrast of CT images in different compression and failure stages, the development of cracks in the specimen is analyzed. According to the average CT number of different scanning layers of CT images, the overall strength of rock specimen and the change of strength after failure are analyzed. The inhomogeneity of initial rock density and the inhomogeneity of damage and failure of specimen during compression failure are obtained. The concept of microelement is introduced, and the distribution curve of CT number of specimen in scanning layer is observed. It is considered that the microelement strength distribution of rock specimen is from weibull distribution, and the variation of microelement strength distribution of rock specimen in different compression failure stage is analyzed. The microelement strength distribution curve will move to the left after the specimen failure. The concept of damage variable is introduced. According to CT images, the damage evolution law of siltstone specimen was studied by analyzing the change of damage variables during compression. The characteristics of rock compression obtained by CT image analysis were analyzed. Finally, the constitutive model should be established to express the damage statistics, and the compression failure process of rock specimen is divided into three stages. The constitutive models of each stage are established, and the total stress-strain curves of siltstone specimens are compared and analyzed. It is concluded that there is a linear relationship between peak stress and confining pressure, and a constitutive model of siltstone specimens under different confining pressures is established. The model is verified.
【學位授予單位】：太原理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TU45

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