Mechanical properties and nondestructive testing of cemented mass of unclassified tailings under freeze-thaw cycles
-
摘要: 尾砂固結排放能有效解決尾砂的處置問題，然而固結后的尾砂堆體多處于地表，其性能受自然環境影響較大。我國北方地區存在廣泛的凍融循環現象，凍融作用會影響固結體的強度和聲電特性，為探究凍融循環條件下全尾砂固結體損傷狀態和機制，以李樓鐵礦全尾砂固結體為研究對象，對經歷不同凍融循環次數的全尾砂固結體試樣進行無側限抗壓強度試驗、掃描電鏡（SEM）試驗、電阻率試驗和超聲波波速試驗，借助Matlab軟件二值化數字圖像處理技術對試樣的表面裂隙進行定量分析，并利用電阻率和超聲波檢測技術對固結體試樣凍融循環損傷進行聯合檢測。結果表明：隨凍融循環次數的增加，固結體的無側限抗壓強度呈指數型減小趨勢，凍融循環早期（0～5次）固結體的強度減少量最多；凍融循環對固結體的損傷是逐漸累積的過程，全尾砂固結體表觀劣化特征發展過程為：微裂隙萌生→裂隙延伸發展→外表層破壞→內部結構破壞；固結體初始強度越大，表面裂紋數越少；內部微觀結構由密實狀態向疏松狀態轉變；固結體無側限抗壓強度與電阻率、超聲波縱波波速呈正相關，遵循對數函數關系，建立了強度?電阻率和強度?超聲波波速無損檢測模型；電阻率和超聲波波速能準確全面地評價凍融循環條件下全尾砂固結體的損傷狀態。Abstract: Tailings consolidation discharge can effectively solve the problem of tailings disposal. However, the tailings pile after consolidation is mostly on the surface, and its performance is greatly affected by the natural environment. Freeze-thaw cycles are widespread in northern China. Freeze-thaw has a great influence on the strength, ultrasonic velocity, and electrical resistance characteristics of cemented mass. To explore the damage evolution state and mechanism of the cemented mass of unclassified tailings under freeze-thaw cycle, in this paper, a series of freeze-thaw tests on a cemented mass of unclassified tailings from the Lilou iron mine were performed. Then the cemented mass samples after different runs of freeze-thaw tests were used to conduct uniaxial compressive strength tests, scanning electron microscopy (SEM) test, resistivity test, and ultrasonic wave velocity test. Quantitative analysis of surface crack images of samples was performed using MATLAB-based binarized digital image processing technology, and a test method for joint testing of freeze-thaw cycle damage of cemented mass specimens using electrical resistivity (ER) and ultrasonic pulse velocity (UPV) testing techniques was proposed. The results indicate that the uniaxial compressive strength (UCS) decreases with increase in freeze-thaw cycles. The greatest decline is for the UCS of cemented mass subjected to 0–5 freeze-thaw cycles. The damage of the cemented mass in the freeze-thaw cycle is a gradual accumulation process. The development process of the apparent degradation characteristics of the cemented mass of unclassified tailings is as follows: micro-fracture initiation → fracture extension development → outer layer failure → internal structure failure; the higher the initial strength of the cemented mass, the fewer the number of surface cracks. The internal microstructure changes from dense to loose. The UCS of the cemented mass is positively correlated with the ER and the UPV, following the logarithmic function relationship, and the nondestructive testing models of UCS-ER and UCS-UPV are established. It is shown that the ER and UPV can accurately and comprehensively evaluate the damage state in cemented mass of unclassified tailings.
-
圖 3 無損檢測. （a）電阻率測試; （b）超聲波波速測試
Figure 3. Nondestructive testing: (a) resistivity test; (b) ultrasonic wave velocity test
圖 4 不同凍融循環次數后固結體的強度變化. （a）灰砂比1∶4; （b）灰砂比1∶8; （c）灰砂比1∶10
Figure 4. Change in the strength of the cemented mass after different freeze-thaw cycles: (a) cement-sand ratio 1∶4; (b) cement-sand ratio 1∶8; (c) cement-sand ratio 1∶10
圖 5 不同凍融循環次數后固結體表面裂隙特征及二值化處理. （a）實際試樣; （b）二值化處理后的試樣
Figure 5. Characteristics of the cemented mass surface cracks after different freeze-thaw cycles and the binarization processing: (a) actual samples; (b) samples after binarization treatment
圖 6 不同凍融循環次數下固結體微觀結構. (a) 0次; (b) 5次; (c) 15次; (d) 20次
Figure 6. Microstructure of cemented mass after different freeze-thaw cycles: (a) 0 times; (b) 5 times; (c) 15 times; (d) 20 times
圖 7 凍融循環過程中固結體的強度與電阻率關系. （a）數據對應（灰砂比1∶4）; （b）擬合曲線(灰砂比1∶4); （c）數據對應(灰砂比1∶8); （d）擬合曲線（灰砂比1∶8）; （e）數據對應（灰砂比1∶10）; （f）擬合曲線（灰砂比1∶10）
Figure 7. Relationship between UCS and ER of samples during freeze-thaw cycles: (a) data correspondence (cement-sand ratio 1∶4); (b) fit curve (cement-sand ratio 1∶4); (c) data correspondence (cement-sand ratio 1∶8); (d) fit curve (cement-sand ratio 1∶8); (e) data correspondence (cement-sand ratio 1∶10); (f) fit curve (cement-sand ratio 1∶10)
圖 8 凍融循環過程中固結體的強度與超聲波波速關系. （a）數據對應（灰砂比1∶4）; （b）擬合曲線（灰砂比1∶4）; （c）數據對應（灰砂比1∶8）; （d）擬合曲線（灰砂比1∶8）; （e）數據對應（灰砂比1∶10）; （f）擬合曲線（灰砂比1∶10）
Figure 8. Relationship between UCS and ER of samples during freeze-thaw cycles: (a) data correspondence (cement-sand ratio 1∶4); (b) fit curve (cement-sand ratio 1∶4); (c) data correspondence (cement-sand ratio 1∶8); (d) fit curve (cement-sand ratio 1∶8); (e) data correspondence (cement-sand ratio 1∶10); (f) fit curve (cement-sand ratio 1∶10)
表 1 全尾砂化學成分（質量分數）
Table 1. Chemical composition of unclassified tailings
% MgO Al2O3 SiO2 CaO Na2O MnO Fe2O3 總計 2.413 3.849 82.052 2.461 0.179 0.021 8.003 98.978 
下載: 導出CSV
表 2 全尾砂基本物理參數
Table 2. Physical parameters of unclassified tailings
密度/(g·cm?3) 容重/(g·cm?3) d10/μm d30/μm d50/μm d60/μm 不均勻系數，Cu 曲率系數，Cc 2.8 1.62 14.55 26.60 38.30 54.27 3.730 0.896
下載: 導出CSV
表 3 不同凍融循環次數后固結體的強度變化
Table 3. Change in the strength of the cemented mass after different freeze-thaw cycles
編號 養護3 d 養護7 d 養護28 d $\sigma $/MPa $\Delta \sigma $/MPa $K$ $\sigma $/MPa $\Delta \sigma $/MPa $K$ $\sigma $/MPa $\Delta \sigma $/MPa $K$ C478-0 1.83 0 0 2.5 0 0 3.82 0 0 C478-5 1.51 0.32 0.17 2.1 0.4 0.16 3.32 0.5 0.13 C478-10 1.33 0.18 0.27 1.85 0.25 0.26 2.96 0.36 0.23 C478-15 1.17 0.16 0.36 1.66 0.19 0.34 2.64 0.32 0.31 C478-20 1.05 0.12 0.43 1.49 0.17 0.40 2.46 0.18 0.36 C878-0 0.78 0 0 1.46 0 0 2.15 0 0 C878-5 0.52 0.26 0.33 1.15 0.31 0.21 1.53 0.62 0.29 C878-10 0.38 0.14 0.51 0.97 0.18 0.34 1.38 0.15 0.36 C878-15 0.31 0.07 0.60 0.84 0.13 0.42 1.24 0.14 0.42 C878-20 0.25 0.06 0.68 0.66 0.18 0.55 1.11 0.13 0.48 C1078-0 0.45 0 0 0.86 0 0 1.32 0 0 C1078-5 0.34 0.11 0.25 0.71 0.15 0.18 1.11 0.21 0.16 C1078-10 0.26 0.08 0.42 0.58 0.13 0.33 0.98 0.13 0.26 C1078-15 0.19 0.07 0.58 0.48 0.1 0.44 0.86 0.12 0.35 C1078-20 0.15 0.04 0.67 0.39 0.09 0.55 0.78 0.08 0.41
下載: 導出CSV
表 4 固結體強度與凍融循環次數的擬合曲線關系式
Table 4. Fitting curve of UCS and the numbers of freeze-thaw cycles
灰砂比 養護齡期/d 擬合曲線公式 a b 相關系數，R2 1∶4 3 $\sigma {\rm{ = }}2.0367{{\rm{e}}^{ - 0.137N}}$ 2.0367 0.137 0.9878 7 $\sigma {\rm{ = }}2.7695{{\rm{e}}^{ - 0.129N}}$ 2.7695 0.129 0.9872 28 $\sigma {\rm{ = 4}}{\rm{.1874}}{{\rm{e}}^{ - 0.111N}}$ 4.1874 0.111 0.9880 1∶8 3 $\sigma {\rm{ = 0}}{\rm{.9535}}{{\rm{e}}^{ - 0.279N}}$ 0.9535 0.279 0.9768 7 $\sigma {\rm{ = 1}}{\rm{.8279}}{{\rm{e}}^{ - 0.203N}}$ 1.8279 0.203 0.9832 28 $\sigma {\rm{ = }}2.3435{{\rm{e}}^{ - 0.158N}}$ 2.3435 0.158 0.9485 1∶10 3 $\sigma {\rm{ = 0}}{\rm{.5929}}{{\rm{e}}^{ - 0.278N}}$ 0.5929 0.278 0.9998 7 $\sigma {\rm{ = 1}}{\rm{.0504}}{{\rm{e}}^{ - 0.197N}}$ 1.0504 0.197 0.9987 28 $\sigma {\rm{ = 1}}{\rm{.4692}}{{\rm{e}}^{ - 0.131N}}$ 1.4692 0.131 0.9904
下載: 導出CSV
表 5 二值化參數值
Table 5. Value of the binarization parameter
編號 養護3 d 養護7 d 養護28 d φ S1 S2 φ S1 S2 φ S1 S2 C878-0 0.007 178838 1329 0.014 177740 2537 0.031 175290 5565 C878-5 0.008 178691 1512 0.021 176748 3757 0.047 172967 8622 C878-10 0.027 175861 4795 0.028 175461 5146 0.055 171324 10059 C878-15 0.003 179549 560 0.011 178442 1987 0.011 178529 2005 C878-20 0.009 178684 1546 0.014 177961 2555 0.019 177348 3368
下載: 導出CSV
www.77susu.com<span id="fpn9h"><noframes id="fpn9h"><span id="fpn9h"></span> <span id="fpn9h"><noframes id="fpn9h"> <th id="fpn9h"></th> <strike id="fpn9h"><noframes id="fpn9h"><strike id="fpn9h"></strike> <th id="fpn9h"><noframes id="fpn9h"> <span id="fpn9h"><video id="fpn9h"></video></span> <ruby id="fpn9h"></ruby> <strike id="fpn9h"><noframes id="fpn9h"><span id="fpn9h"></span> -
參考文獻
[1] Meng Y H, Ni W, Zhang Y Y. Current state of ore tailings reusing and its future development in China. China Mine Eng, 2010, 39(5): 4 doi: 10.3969/j.issn.1672-609X.2010.05.003孟躍輝, 倪文, 張玉燕. 我國尾礦綜合利用發展現狀及前景. 中國礦山工程, 2010, 39(5):4 doi: 10.3969/j.issn.1672-609X.2010.05.003 [2] Deng W, Jiang D B, Yang B, et al. Comprehensive utilization status and existing problems of iron tailings in China. Mod Min, 2012(9): 1 doi: 10.3969/j.issn.1674-6082.2012.09.001鄧文, 江登榜, 楊波, 等. 我國鐵尾礦綜合利用現狀和存在的問題. 現代礦業, 2012(9):1 doi: 10.3969/j.issn.1674-6082.2012.09.001 [3] Hou Y B, Tang J, Wei S X. Research on tailings’ cementation and discharging technology. Met Mine, 2011(6): 59侯運炳, 唐杰, 魏書祥. 尾礦固結排放技術研究. 金屬礦山, 2011(6):59 [4] Yang J, Qian Z Q, Wang J. Effects of repeated freezing and thawing and high temperature aging on the solidification and stabilization of arsenic contaminated soil. Environ Sci, 2017, 38(11): 4844楊潔, 錢趙秋, 王旌. 反復凍融與高溫老化對砷污染土壤固化穩定化效果的影響. 環境科學, 2017, 38(11):4844 [5] Fener M, Ince I. Effects of the freeze–thaw (F–T) cycle on the andesitic rocks (Sille-Konya/Turkey) used in construction building. J Afr Earth Sci, 2015, 109: 96 doi: 10.1016/j.jafrearsci.2015.05.006 [6] Xu G M, Liu Q S. Analysis of mechanism of rock failure due to freeze-thaw cycling and mechanical testing study on frozen-thawed rocks. Chin J Rock Mech Eng, 2005, 24(17): 3076 doi: 10.3321/j.issn:1000-6915.2005.17.012徐光苗, 劉泉聲. 巖石凍融破壞機理分析及凍融力學試驗研究. 巖石力學與工程學報, 2005, 24(17):3076 doi: 10.3321/j.issn:1000-6915.2005.17.012 [7] Fu W, Wang R. Experimental study of electrical resistivity and deformation characteristics of saturated silty clay during repeated freeze-thaw cycles. Rock Soil Mech, 2010, 31(3): 769 doi: 10.3969/j.issn.1000-7598.2010.03.018付偉, 汪稔. 飽和粉質黏土反復凍融電阻率及變形特性試驗研究. 巖土力學, 2010, 31(3):769 doi: 10.3969/j.issn.1000-7598.2010.03.018 [8] Fu W, Wang R, Hu M J, et al. Study of relationship between uniaxial compressive strength and electrical resistivity of frozen soil under different temperatures. Rock Soil Mech, 2009, 30(1): 73 doi: 10.3969/j.issn.1000-7598.2009.01.011付偉, 汪稔, 胡明鑒, 等. 不同溫度下凍土單軸抗壓強度與電阻率關系研究. 巖土力學, 2009, 30(1):73 doi: 10.3969/j.issn.1000-7598.2009.01.011 [9] Liu Q S, Huang S B, Kang Y S, et al. Fatigue damage model and evaluation index for rock mass under freezing-thawing cycles. Chin J Rock Mech Eng, 2015, 34(6): 1116劉泉聲, 黃詩冰, 康永水, 等. 巖體凍融疲勞損傷模型與評價指標研究. 巖石力學與工程學報, 2015, 34(6):1116 [10] Wei Z A, Yang Y H, Xu J J, et al. Experiment study on the mechanical properties of frozen tailings by uniaxial compression tests. J Northeastern Univ Nat Sci, 2016, 37(1): 123魏作安, 楊永浩, 徐佳俊, 等. 人工凍結尾礦力學特性單軸壓縮試驗研究. 東北大學學報: 自然科學版, 2016, 37(1):123 [11] Chang D, Liu J K, Li X, et al. Experiment study of effects of freezing-thawing cycles on mechanical properties of Qinghat-Tibet silty sand. Chin J Rock Mech Eng, 2014, 33(7): 1496常丹, 劉建坤, 李旭, 等. 凍融循環對青藏粉砂土力學性質影響的試驗研究. 巖石力學與工程學報, 2014, 33(7):1496 [12] Deng D Q, Gao Y T, Wu S C, et al. Integrality detection of backfill based on acoustic wave velocity testing. J Univ Sci Technol Beijing, 2010, 32(10): 1248鄧代強, 高永濤, 吳順川, 等. 基于聲波測速的充填體完整性檢測. 北京科技大學學報, 2010, 32(10):1248 [13] Li J R, Gao J G, Wang Y H. Supersonic wave testing on concrete crack depth and analysis of crack initiation. Rock Soil Mech, 2001, 22(3): 291 doi: 10.3969/j.issn.1000-7598.2001.03.012李俊如, 高建光, 王耀輝. 超聲波檢測混凝土裂縫及裂縫成因分析. 巖土力學, 2001, 22(3):291 doi: 10.3969/j.issn.1000-7598.2001.03.012 [14] Wang W H, Wan J. The experimental study on the role of freeze-thaw cycles on uniaxial compressive strength influence in carbonate saline soil. J Changchun Inst Technol Nat Sci Ed, 2016, 17(3): 6王文華, 萬健. 凍融循環作用對碳酸鹽漬土單軸抗壓強度影響的試驗研究. 長春工程學院學報: 自然科學版, 2016, 17(3):6 [15] Xu W B, Du J H, Song W D, et al. Experiment on the mechanism of consolidating backfill body of extra-fine grain unclassified tailings and cementitious materials. Rock Soil Mech, 2013, 34(8): 2295徐文彬, 杜建華, 宋衛東, 等. 超細全尾砂材料膠凝成巖機理試驗. 巖土力學, 2013, 34(8):2295 [16] Hu X T, Liang B, Chen Y J, et al. Mechanical and microstructural properties changes of solidified sewage sludge due to cyclic freezing and thawing. Rock Soil Mech, 2016, 37(5): 1317胡學濤, 梁冰, 陳億軍, 等. 凍融循環對固化污泥力學及微觀結構特性影響. 巖土力學, 2016, 37(5):1317 [17] Cheng H Y, Wu S C, Wu A X, et al. Grading characterization and yield stress prediction based on paste stability coefficient. Chin J Eng, 2018, 40(10): 1168程海勇, 吳順川, 吳愛祥, 等. 基于膏體穩定系數的級配表征及屈服應力預測. 工程科學學報, 2018, 40(10):1168 [18] Viran P A G, Binal A. Effects of repeated freeze–thaw cycles on physico-mechanical properties of cohesive soils. Arabian J Geosci, 2018, 11: 250 doi: 10.1007/s12517-018-3592-5 [19] Zhang Y, Bing H, Yang C S. Influences of freeze-thaw cycles on mechanical porperties of silty clay based on SEM and MIP test. Chin J Rock Mech Eng, 2015, 34(Suppl 1): 3597張英, 邴慧, 楊成松. 基于SEM和MIP的凍融循環對粉質黏土強度影響機制研究. 巖石力學與工程學報, 2015, 34(增刊1): 3597 [20] Koohestani B. Effect of saline admixtures on mechanical and microstructural properties of cementitious matrices containing tailings. Construction Building Mater, 2017, 156: 1019 doi: 10.1016/j.conbuildmat.2017.09.048 [21] Aldaood A, Bouasker M, Al-Mukhtar M. Impact of freeze–thaw cycles on mechanical behaviour of lime stabilized gypseous soils. Cold Regions Sci Technol, 2014, 99: 38 doi: 10.1016/j.coldregions.2013.12.003 -
點擊查看大圖
計量
- 文章訪問數: 1096
- HTML全文瀏覽量: 671
- PDF下載量: 20
- 被引次數: 0
