發(fā)布時(shí)間：2018-03-27 21:35

  本文選題：準(zhǔn)脆性材料　切入點(diǎn)：巖石　出處：《天津大學(xué)》2014年博士論文

【摘要】：巖石類準(zhǔn)脆性材料的力學(xué)性能和損傷失效是地下空間開發(fā)、水利水電建設(shè)、巖石隧道掘進(jìn)、礦產(chǎn)資源開采等領(lǐng)域所關(guān)注的基礎(chǔ)科學(xué)問題。與此同時(shí)，從實(shí)驗(yàn)的角度測(cè)量和表征損傷是研究巖石各種損傷破壞過程的基礎(chǔ)性和關(guān)鍵性工作。本文圍繞準(zhǔn)脆性材料損傷失效問題，在數(shù)字圖像相關(guān)全場(chǎng)測(cè)量與實(shí)驗(yàn)數(shù)據(jù)統(tǒng)計(jì)分析的基礎(chǔ)上，對(duì)巖石材料的損傷演化規(guī)律及失效機(jī)制開展研究，論文選題具有重要的工程背景與科學(xué)意義。 本文通過數(shù)字圖像相關(guān)技術(shù)（DIC）對(duì)巖石壓縮失效過程中的損傷演化與局部化進(jìn)行系統(tǒng)的實(shí)驗(yàn)研究，實(shí)時(shí)給出了不同載荷水平下巖石表面的變形位移場(chǎng)和應(yīng)變場(chǎng)。在實(shí)驗(yàn)結(jié)果分析的基礎(chǔ)上，本文將最大拉應(yīng)變1作為描述損傷的力學(xué)參量，進(jìn)一步對(duì)實(shí)驗(yàn)給出的所有的實(shí)驗(yàn)數(shù)據(jù)進(jìn)行統(tǒng)計(jì)。統(tǒng)計(jì)分析結(jié)果表明，全場(chǎng)所有測(cè)點(diǎn)的應(yīng)變平均值基本隨壓力載荷呈線性增長(zhǎng)，反映大部分測(cè)點(diǎn)在加載過程中處于均勻變形狀態(tài)；其中前10%左右的較大應(yīng)變點(diǎn)的平均值在損傷局部化及裂紋萌生階段表現(xiàn)為非線性快速增長(zhǎng)，表明這些點(diǎn)主導(dǎo)了巖石的損傷演化和裂紋擴(kuò)展。 在DIC全場(chǎng)測(cè)量與實(shí)驗(yàn)數(shù)據(jù)統(tǒng)計(jì)分析的基礎(chǔ)上，首次提出了損傷演化雙因子實(shí)驗(yàn)表征方法。以實(shí)時(shí)測(cè)量的最大應(yīng)變1作為損傷演化的關(guān)鍵參量，進(jìn)行實(shí)驗(yàn)數(shù)據(jù)統(tǒng)計(jì)與歸一化分析，提出了損傷局部化因子Lf，描述損傷的空間局部化程度，提出了損傷程度因子Df，描述損傷的程度，并給出了雙因子曲線隨壓力載荷的變化。本文還將雙因子方法應(yīng)用于巴西圓盤、壓頭壓入、循環(huán)加卸載等不同工況與不同試件的損傷演化測(cè)量，實(shí)驗(yàn)結(jié)果發(fā)現(xiàn)，雙因子曲線均在損傷局部化階段發(fā)生交匯之后曲線出現(xiàn)拐點(diǎn)，，表明損傷的匯聚串接已導(dǎo)致裂紋基本形成，驗(yàn)證了這一方法對(duì)準(zhǔn)脆性材料損傷演化定量表征的適用性。 論文開展了巖石在壓頭載荷、加卸載、三點(diǎn)彎等不同工況作用下的損傷斷裂實(shí)驗(yàn)研究。分析了壓頭載荷作用下巖石裂紋擴(kuò)展的機(jī)理，給出了壓頭載荷與裂紋長(zhǎng)度之間的關(guān)系。實(shí)驗(yàn)發(fā)現(xiàn)加卸載過程中存在能量耗散，殘余變形隨循環(huán)載荷的增加而增大，并對(duì)加卸載過程中的裂紋行為進(jìn)行了分析。DIC結(jié)合聲發(fā)射技術(shù)研究了巖石三點(diǎn)彎實(shí)驗(yàn)損傷斷裂問題，綜合聲發(fā)射振鈴計(jì)數(shù)率與實(shí)驗(yàn)位移、應(yīng)變場(chǎng)分析發(fā)現(xiàn)，裂紋起裂載荷約為峰值載荷的80%。利用DIC位移場(chǎng)分析得到了裂紋張開位移以及裂紋擴(kuò)展全過程。
[Abstract]:The mechanical properties and damage failure of rock quasi brittle materials are the basic scientific problems in the fields of underground space development, water conservancy and hydropower construction, rock tunneling, mineral resource mining and so on. Measuring and characterizing damage from the point of view of experiment is the basic and key work to study the damage and failure process of rock. This paper focuses on the damage failure problem of quasi brittle materials. On the basis of digital image correlation full-field measurement and statistical analysis of experimental data, the damage evolution law and failure mechanism of rock materials are studied. This paper has important engineering background and scientific significance. In this paper, a systematic experimental study on damage evolution and localization during compression failure of rock is carried out by means of digital image correlation technique (DICs). The deformation displacement field and strain field of rock surface under different load levels are given in real time. Based on the analysis of experimental results, the maximum tensile strain 1 is taken as the mechanical parameter to describe the damage. The results of statistical analysis show that the average strain of all the measured points increases linearly with the pressure load, which shows that most of the measured points are in a uniform deformation state during the loading process. The average values of the first 10% of the large strain points show nonlinear and rapid growth during the damage localization and crack initiation stages, indicating that these points dominate the damage evolution and crack propagation of rocks. On the basis of DIC field measurement and statistical analysis of experimental data, a double factor experimental characterization method for damage evolution is proposed for the first time. The maximum strain 1 measured in real time is taken as the key parameter of damage evolution. Based on the statistics and normalization analysis of experimental data, a damage localization factor (LF) is proposed to describe the degree of damage localization in space, and a damage degree factor (Df) is proposed to describe the degree of damage. The change of double factor curve with pressure load is also given. The method is also applied to the damage evolution measurement of Brazilian disc, head indentation, cyclic loading and unloading under different working conditions and different specimens, and the experimental results show that, The curve inflection points appear after the intersection of the two-factor curves in the damage localization stage, which indicates that the convergence and serial connection of the damage has led to the basic formation of the crack, which verifies the applicability of this method to the quantitative characterization of the damage evolution of brittle materials. In this paper, the damage and fracture experiments of rock under different working conditions, such as head load, loading and unloading, three point bending, are carried out, and the mechanism of rock crack growth under pressure head load is analyzed. The relationship between head load and crack length is given. It is found that there is energy dissipation during loading and unloading, and the residual deformation increases with the increase of cyclic load. The crack behavior during loading and unloading is analyzed. DIC combined with acoustic emission technique is used to study the damage and fracture of rock in three-point bending experiment. The crack initiation load is about 80 parts of the peak load. The crack opening displacement and crack propagation process are obtained by DIC displacement field analysis.
【學(xué)位授予單位】：天津大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2014
【分類號(hào)】：TU45

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 鄭捷,姚孝新,陳楻;巖石變形局部化的實(shí)驗(yàn)研究[J];地球物理學(xué)報(bào);1983年06期

2 孟召平;張吉昌;Joachim Tiedemann;;煤系巖石物理力學(xué)參數(shù)與聲波速度之間的關(guān)系[J];地球物理學(xué)報(bào);2006年05期

3 錢七虎;;中國(guó)巖石工程技術(shù)的新進(jìn)展[J];中國(guó)工程科學(xué);2010年08期

4 黎立云;謝和平;鞠楊;馬旭;王利;;巖石可釋放應(yīng)變能及耗散能的實(shí)驗(yàn)研究[J];工程力學(xué);2011年03期

5 史紅健;計(jì)宏偉;何小元;;一種三維變形光學(xué)測(cè)量系統(tǒng)及微結(jié)構(gòu)力學(xué)性能測(cè)試應(yīng)用[J];光學(xué)學(xué)報(bào);2011年03期

6 張克實(shí),Brocks Wolfgang;Chaboche熱粘塑性損傷模型的應(yīng)用研究[J];航空動(dòng)力學(xué)報(bào);2002年05期

7 ;Comparison of the fracture process of the rubberized concrete and plain concrete under bending load[J];Science China(Technological Sciences);2010年06期

8 葛修潤(rùn),任建喜,蒲毅彬,馬巍,朱元林;巖石細(xì)觀損傷擴(kuò)展規(guī)律的CT實(shí)時(shí)試驗(yàn)[J];中國(guó)科學(xué)E輯:技術(shù)科學(xué);2000年02期

9 王夢(mèng)恕;;中國(guó)鐵路、隧道與地下空間發(fā)展概況[J];隧道建設(shè);2010年04期

10 李喜德;散斑檢測(cè)技術(shù)及其應(yīng)用[J];理化檢驗(yàn)(物理分冊(cè));2004年05期

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