玄武巖三維細觀孔隙模型重構與直接拉伸數值試驗

郎穎嫻; 梁正召; 董卓

doi:10.13374/j.issn2095-9389.2019.08.005

玄武巖三維細觀孔隙模型重構與直接拉伸數值試驗

doi: 10.13374/j.issn2095-9389.2019.08.005

郎穎嫻^{1, 2},
梁正召^{1, 2, ,},
董卓^{1, 2}

1.
大連理工大學海岸和近海工程國家重點實驗室, 大連 116024
2.
大連理工大學巖石破裂與失穩研究所, 大連 116024

基金項目:

國家重點研發計劃資助項目 2016YFB0201000

國家自然科學基金資助項目 51779031

國家自然科學基金資助項目 51878190

詳細信息

通訊作者:
梁正召, E-mail: LiangZZ@dlut.edu.cn

中圖分類號: TG142.71
計量
- 文章訪問數: 937
- HTML全文瀏覽量: 359
- PDF下載量: 27
- 被引次數: 0
出版歷程
- 收稿日期: 2018-07-18
- 刊出日期: 2019-08-01

Three-dimensional microscopic model reconstruction of basalt and numerical direct tension tests

LANG Ying-xian^{1, 2},
LIANG Zheng-zhao^{1, 2
, ,},
DONG Zhuo^{1, 2}

1.
State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian 116024, China
2.
Institute of Rock Instability & Seismicity Research, Dalian University of Technology, Dalian 116024, China

More Information

Corresponding author: LIANG Zheng-zhao, E-mail: LiangZZ@dlut.edu.cn

摘要

摘要: 由于巖石材料的不透明性和多孔隙特性, 通過傳統的物理試驗或數值模擬很難真實體現其內部三維細觀結構. 本文基于CT掃描技術、邊緣檢測算法、濾波算法、三維點陣映射與重構算法, 構建了可以表征玄武巖試樣內部孔隙結構的三維細觀非均勻數值模型. 結合并行計算進行直接拉伸數值試驗, 研究了內部孔隙結構特征對試樣破壞機制及抗拉強度的影響. 研究結果表明: 加載初期在試樣孔隙處產生初始裂紋, 隨著荷載的增加初始裂紋逐漸沿橫向擴展最終形成宏觀拉伸破壞裂紋, 并且孔隙含量和分布位置對試樣拉伸斷裂的位置具有重要影響. 隨著孔隙率增高, 試樣破壞過程中的聲發射數目和能量逐漸減小. 拉伸破壞模式呈現脆性破壞特征, 同時孔隙的存在削弱了試樣的抗拉強度.
- 玄武巖 /
- 孔隙 /
- CT掃描 /
- 數字圖像處理 /
- 有限元
Abstract: The presence of discontinuities and randomly distributed pores in basalt specimens greatly affects their engineering properties, such as the failure mechanism and strength. Therefore, investigating the mechanical and fracture behaviors of basalt affected by the pre-existing defects is important for underground engineering, mining engineering, foundation engineering, and rock breaking and blasting. Laboratory tests have been widely used to research the failure mechanism of rocks under different conditions. However, it is difficult to clearly show the internal or spatial crack evolution during rock failure process in laboratory tests. Recently, X-ray computerized tomography (CT) and numerical tests have been used to detect the internal microstructures of rock specimens and to study their failure mechanism and strength. In addition, tensile strength is an important mechanical property of rock material. The direct tensile test is theoretically the simplest and most effective method for understanding the tensile behavior of rock. However, it is difficult to carry out in practical condition, because the sample processing and test procedures are complicated, also the experimental process of each sample cannot be repeated and has limited results. Due to the opacity of rocks, it is difficult to examine the three-dimensional internal structures of rocks through traditional physical and numerical experiments. In the present research, a 3D numerical method was proposed for simulating porous rock failure based on CT technology, the edge detection algorithm, filtering algorithm, and 3D matrix mapping method. Direct tensile tests were carried out based on the parallel finite element method to study the effect of the porosity and pore distribution on the failure mechanism and tensile strength. The results indicate that initial cracks at the beginning of loading usually occur in pores, and then with the raising of load the initial cracks propagate along the direction perpendicular to the loading direction and eventually form macroscopic tensile cracks. The porosity and pore distribution have significant influences on the position of macroscopic tensile cracks. The acoustic emission (AE) event numbers and the accumulative AE energy are gradually decreased as the porosity increased. In addition, the brittle failure primarily determines the tensile failure mode and the presence of pores weakens the tensile strength of basalt samples.
- basalt /
- pore /
- CT /
- digital image /
- finite element method

HTML全文

圖 1 玄武巖試樣

Figure 1. Basalt samples

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圖 2 CT掃描圖像預處理. (a) CT圖像; (b) 二值化處理; (c) 5×5濾波窗口; (d) 10×10濾波窗口

Figure 2. CT images of sample 1 after processing: (a) CT images; (b) binarization processing; (c) 5×5 filtering window; (d) 10×10 filtering window

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圖 3 掃描線上灰度變化曲線

Figure 3. Gray values along the scanned line processing

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圖 4 細觀圖像轉化為矢量化結構

Figure 4. Single-layer grid model based on a structural characterization

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圖 5 試樣1實體模型與數值模型

Figure 5. Physical and numerical models of sample 1

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圖 6 玄武巖試樣不同視角下拉伸斷裂形態. (a) 試樣1 (Step=18); (b) 試樣2 (Step=12); (c) 試樣3 (Step=15); (d) 試樣4 (Step=15); (e) 試樣5 (Step=15)

Figure 6. Crack morphologies of basalt specimens under direct tensile stress: (a) sample 1 (Step=18); (b) sample 2 (Step=12); (c) sample 3 (Step=15); (d) sample 4 (Step=15); (e) sample 5 (Step=15)

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圖 7 試樣1裂紋擴展圖. (a) Step = 1; (b) Step = 8-(7); (c) Step = 8-(15); (d) Step = 15; (e) 內部切片圖

Figure 7. Crack propagation process in sample 1: (a) Step = 1; (b) Step = 8-(7); (c) Step = 8-(15); (d) Step = 15; (e) internal slice figure

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圖 8 裂紋擴展過程和單元損傷圖. (a) 試樣2裂紋擴展圖; (b) 試樣3裂紋擴展圖及單元損傷圖; (c) 試樣4裂紋擴展圖; (d) 試樣5單元損傷圖

Figure 8. Images showing crack propagation process and element damage: (a) the crack propagation of sample 2; (b) the crack propagation and element damage of sample 3; (c) the crack propagation of sample 4; (d) the element damage of sample 5

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圖 9 聲發射數目

Figure 9. AE counts

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圖 10 累積聲發射能量

Figure 10. Accumulative AE energy values

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圖 11 應力-應變曲線

Figure 11. Stress-strain curves

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圖 12 抗拉強度與孔隙率的關系

Figure 12. Relationship between tensile strength and porosity

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表 1 模型參數

Table 1. Mechanical parameters of the numerical model

材料彈性模量/GPa 泊松比摩擦角/(°) 抗壓強度/MPa

玄武巖 26 0.26 38 92

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表 2 模型計算孔隙率

Table 2. Porosities calculated by the numerical model

模型序號計算孔隙率/%

試樣1 7.78

試樣2 8.52

試樣3 25.75

試樣4 13.95

試樣5 10.43

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