Experimental study on the dynamic mechanical characteristics of slope rock under low-temperature conditions
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摘要: 我國多年凍結區和季節性凍結區面積廣泛，在這些地區進行工程建設和礦產資源開采必須考慮特殊的地質和氣候條件，其中寒區邊坡的穩定性問題值得研究。以位于西藏自治區的玉龍銅礦為例，礦區平均海拔約4000 m，最冷月日平均最低氣溫約?20 ℃，凍結期長，邊坡穩定性受凍融作用顯著，凍結巖層給爆破開挖帶來諸多困難，制約了礦山生產效率。為研究低溫條件下邊坡巖石的動態力學特性，從西藏玉龍銅礦邊坡鉆取了大理巖試樣，借助含低溫控制系統的分離式霍普金森壓桿（SHPB）實驗系統，對常溫干燥、常溫飽水和低溫凍結三種狀態的巖樣進行了動態拉壓力學實驗，以探究溫度、含水量對巖石動態力學性質的影響。試驗結果表明：(1)受低溫水冰相變和巖石基質冷縮的共同影響，?20 ℃凍結巖樣的平均單軸動態壓縮、拉伸強度較常溫下有所增大。其中，巖石基質的冷縮現象是造成凍結巖石強度顯著提高的主要原因。四種應變率下，壓縮應力分別增大1.30、1.62、1.41、1.43倍，拉伸應力分別增大1.36、1.28、1.22和1.29倍；(2) 受孔隙水軟化影響，飽水巖樣動態強度小于干燥巖樣，因此同一應變率下的實驗數據滿足規律，即凍結巖樣強度最高，干燥次之，飽水最低；(3)相同應變率下，飽水大理石的動態沖擊破碎時間最長，且隨應變率增大下降速度最快，同時，在相同應變率下，凍結巖樣破碎耗能大于常溫耗能，隨應變率變化增幅最大。Abstract: China has large regions that freeze seasonally or multiple times a year. Special geological and climatic conditions must be considered for the engineering construction and mining of mineral resources in these regions, and slope stability in cold regions merits study. Taking the Yulong Copper Mine in the Tibet Autonomous Region as an example, the average altitude of this mining area is approximately 4000 m, the average daily minimum temperature in the coldest month is approximately ?20 ℃, and the freezing period is long. Slope stability is considerably affected by freezing and thawing, and frozen rock creates several challenges to blasting and excavation, thereby restricting mine production efficiency. To study the dynamic mechanical characteristics of slope rock under low-temperature conditions, marble samples are drilled from the slope of the Yulong Copper Mine. With the help of the SHPB experimental system with a low-temperature control system, dynamic compression and tensile mechanics experiments are performed on rock samples under normal temperature and dry conditions, normal temperature and adequate water conditions, and low-temperature freezing conditions to explore the influence of temperature and water content on rock dynamic mechanical properties. The experimental results show that (1) the average uniaxial dynamic compression and tensile strength of frozen rock samples at ?20 ℃ are increased compared with those at room temperature under the joint influence of water/ice phase transformation at low temperature and rock matrix cold shrinkage. Among these phenomena, the latter is the main reason that the strength of frozen rock increases substantially. Under four strain rates, the compressive stress increased by 1.30, 1.62, 1.41, and 1.43 times, and the tensile stress increased by 1.36, 1.28, 1.22, and 1.29 times, respectively. (2) Under the influence of pore water softening, a saturated rock sample has less dynamic strength than a dry rock sample. Therefore, the experimental data under the same strain rate show that the strength of a rock sample follows the order of frozen > dry > saturated. (3) For a given strain rate, the dynamic impact crushing time of saturated marble is the longest, and the decrease with increasing strain rate is the fastest. For a given strain rate, the crushing energy consumption is larger for a rock sample at freezing temperature than at normal temperature and increases greatly with increasing strain rate.
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Key words:
- cold region slope /
- frozen rock /
- SHPB /
- dynamic characteristic /
- broken characteristics
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圖 1 含低溫控制系統的SHPB實驗系統圖
Figure 1. Diagram of the SHPB experimental system with a cryogenic control system
圖 3 應力平衡圖. (a)原始信號圖; (b)應力平衡圖
Figure 3. Stress balance diagram: (a) original signal diagram; (b) stress balance diagram
圖 5 不同應變率下干燥大理巖的壓縮、拉伸的
$ \sigma $ ?$ \varepsilon $ 曲線. (a)壓縮應力應變曲線; (b)拉伸應力應變曲線Figure 5.
$ \sigma $ –$ \varepsilon $ curves of the compression and tension of dry marble at different strain rates: (a) compressive stress–strain curves; (b) tensile stress–strain curves
圖 6 不同應變率下飽水大理巖的壓縮、拉伸的
$ \sigma $ ?$ \varepsilon $ 曲線. (a)壓縮應力應變曲線; (b)拉伸應力應變曲線Figure 6.
$ \sigma $ –$ \varepsilon $ curves of the compression and tension of saturated marble at different strain rates: (a) compressive stress–strain curves; (b) tensile stress–strain curves
圖 7 不同應變率下凍結大理巖的壓縮、拉伸的
$ \sigma $ ?$ \varepsilon $ 曲線. (a)壓縮應力應變曲線; (b)拉伸應力應變曲線Figure 7.
$ \sigma $ –$ \varepsilon $ curves of the compression and tension of frozen marble at different strain rates: (a) compressive stress–strain curves; (b) tensile stress–strain curves
圖 8 不同狀態巖樣壓縮峰值應力的應變率效應. (a)干燥; (b)飽水；(c)凍結
Figure 8. Strain rate effect of the peak compressive stress of rock samples under different states: (a) drying; (b) saturated; (c) frozen
圖 9 不同狀態巖樣拉伸峰值應力的應變率效應. (a)干燥; (b)飽水; (c)凍結
Figure 9. Strain rate effect of the peak tensile stress of rock samples in different states: (a) drying; (b) saturated; (c) frozen
圖 10 不同狀態巖樣動態峰值應力差異. (a)壓縮強度; (b)拉伸強度
Figure 10. Dynamic peak stress differences of rock samples in different states: (a) compressive strength; (b) tensile strength
圖 11 巖樣內部結構隨溫度變化示意圖. (a)常溫; (b) ?4 ℃; (c) ?20 ℃
Figure 11. Variation in the internal structure of a rock sample with temperature: (a) room temperature; (b) ?4 ℃; (c) ?20 ℃
圖 12 不同狀態巖樣破碎時間與
${\dot \varepsilon ^{{{ - }}{4}/{7}}}$ 的關系. (a)干燥; (b)飽水; (c)凍結Figure 12. Relationship between the crushing time and
${\dot \varepsilon ^{{{ - }}{4}/{7}}}$ of rock samples in different states: (a) drying; (b) saturated; (c) frozen
圖 13 不同狀態巖樣破碎能量與
${\dot \varepsilon ^{{6}/{7}}}$ 的關系. (a)干燥; (b)飽水; (c)凍結Figure 13. Relationship between the crushing time and
${\dot \varepsilon ^{{6}/{7}}}$ of rock samples in different states: (a) drying; (b) saturated; (c) frozen表 1 巖樣基本物理學參數
Table 1. Basic physical parameters of rock samples
Lithology Drying P-wave velocity/(m?s?1) Dry
density/(kg?m?3)Saturated density /
(kg?m?3)NMR
porosity/%Marble 4210.55 2704.22 2706.95 0.25 
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中文字幕在线观看表 2 巖石壓縮破碎能耗計算結果
Table 2. Calculation results of energy consumption for rock crushing
State of the specimens Specimen number Average strain rate/s?1 Broken time,
T/μsCrushing energy /J Dry A11 46.23 100 58.44 A12 54.97 88 70.07 A13 67.12 77 82.31 A14 75.13 72 93.02 Saturated A21 45.28 133 54.12 A22 54.41 117 66.41 A23 64.13 108 79.14 A24 76.83 89 109.87 Frozen A31 45.77 110 50.45 A32 55.57 80 85.46 A33 64.02 75 110.80 A34 76.03 71 117.50
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參考文獻
[1] Hou Y B, Zhang X, Li P, et al. Mechanical properties and nondestructive testing of cemented mass of unclassified tailings under freeze-thaw cycles. Chin J Eng, 2019, 41(11): 1433侯運炳, 張興, 李攀, 等. 凍融循環對全尾砂固結體力學性能影響及無損檢測研究. 工程科學學報, 2019, 41(11):1433 [2] Li C H, Xiao Y G, Wang Y, et al. Review and prospects for understanding deformation and failure of rock slopes in cold regions with high altitude. Chin J Eng, 2019, 41(11): 1374李長洪, 肖永剛, 王宇, 等. 高海拔寒區巖質邊坡變形破壞機制研究現狀及趨勢. 工程科學學報, 2019, 41(11):1374 [3] Yang Y, Yang R S. “Frostbite effect” of red sandstone under high strain rates. Chin J Eng, 2019, 41(10): 1249楊陽, 楊仁樹. 高應變率下紅砂巖“凍傷效應”. 工程科學學報, 2019, 41(10):1249 [4] Yan B Q, Ren F H, Cai M F, et al. A review of the research on physical and mechanical properties and constitutive model of rock under THMC multi-field coupling. Chin J Eng, 2020, 42(11): 1389顏丙乾, 任奮華, 蔡美峰, 等. THMC多場耦合作用下巖石物理力學性能與本構模型研究綜述. 工程科學學報, 2020, 42(11):1389 [5] Gao F, Xiong X, Zhou K P, et al. Strength deterioration model of saturated sandstone under freeze-thaw cycles. Rock Soil Mech, 2019, 40(3): 926高峰, 熊信, 周科平, 等. 凍融循環作用下飽水砂巖的強度劣化模型. 巖土力學, 2019, 40(3):926 [6] Dong F F, Zhu T T, Qu Z J. Particle flow-based investigation on the tensile behaviours of rock after freeze-thaw treatment. J Hebei Univ Eng (Nat Sci Ed) , 2021, 38(3): 22董方方, 朱譚譚, 屈子健. 基于顆粒流的富水巖石凍融后拉伸力學行為研究. 河北工程大學學報(自然科學版), 2021, 38(3):22 [7] Wen L, Li X B, Tang H Y, et al. Study of physico-mechanical characteristics of rock under different frozen-thawed circle temperature range and its engineering application. Eng Mech, 2017, 34(5): 247聞磊, 李夕兵, 唐海燕, 等. 變溫度區間凍融作用下巖石物理力學性質研究及工程應用. 工程力學, 2017, 34(5):247 [8] Lu X F, Jiang J G, Chen J X, et al. Damage evolution law of rock under freeze-thaw cycle. China Water Transp, 2021, 21(9): 107盧雪峰, 蔣建國, 陳建行, 等. 凍融循環作用下巖石的損傷演化規律. 中國水運(下半月), 2021, 21(9):107 [9] Zhang H M, Mu N N. Study on meso-damage of freeze-thaw rocks based on 3d reconstruction. Mech Eng, 2021, 43(5): 687張慧梅, 慕娜娜. 基于三維重構的凍融巖石細觀損傷研究. 力學與實踐, 2021, 43(5):687 [10] Yamabe T, Neaupane K M. Determination of some thermo-mechanical properties of Sirahama sandstone under subzero temperature condition. Int J Rock Mech Min Sci, 2001, 38(7): 1029 doi: 10.1016/S1365-1609(01)00067-3 [11] Park C, Synn J H, Shin H S, et al. Experimental study on the thermal characteristics of rock at low temperatures. Int J Rock Mech Min Sci, 2004, 41: 81 doi: 10.1016/j.ijrmms.2004.03.023 [12] Zhao T, Yang G S, Ren J T, et al. Influence of temperatures on the mechanical properties of frozen saturated sandstone. J Xi’an Univ Sci Technol, 2020, 40(6): 996趙濤, 楊更社, 任俊童, 等. 不同負溫對凍結飽和砂巖力學特性的影響. 西安科技大學學報, 2020, 40(6):996 [13] Liu B, Sun Y D, Yuan Y F, et al. Strength characteristics of frozen sandstone with different water content and its strengthening mechanism. J China Univ Min Technol, 2020, 49(6): 1085劉波, 孫顏頂, 袁藝峰, 等. 不同含水率凍結砂巖強度特性及強度強化機制. 中國礦業大學學報, 2020, 49(6):1085 [14] Wei Y, Yang G S, Shen Y J, et al. Creep test and constitutive model of Cretaceous saturated frozen sandstone. Rock Soil Mech, 2020, 41(8): 2636魏堯, 楊更社, 申艷軍, 等. 白堊系飽和凍結砂巖蠕變試驗及本構模型研究. 巖土力學, 2020, 41(8):2636 [15] Shan R L, Bai Y, Sun P F, et al. Study of triaxial creep mechanical properties and constitutive model of frozen stratified red sandstone. J China Univ Min Technol, 2019, 48(1): 12單仁亮, 白瑤, 孫鵬飛, 等. 凍結層狀紅砂巖三軸蠕變特性及本構模型研究. 中國礦業大學學報, 2019, 48(1):12 [16] Yang G S, Wei Y, Shen Y J, et al. Mechanical behavior and strength forecast model of frozen saturated sandstone under triaxial compression. Chin J Rock Mech Eng, 2019, 38(4): 683楊更社, 魏堯, 申艷軍, 等. 凍結飽和砂巖三軸壓縮力學特性及強度預測模型研究. 巖石力學與工程學報, 2019, 38(4):683 [17] Shan R L, Song L W, Bai Y, et al. Model test studies of damage evaluation of frozen rock wall under blasting loads. Chin J Rock Mech Eng, 2014, 33(10): 1945單仁亮, 宋立偉, 白瑤, 等. 爆破作用下凍結巖壁損傷評價的模型試驗研究. 巖石力學與工程學報, 2014, 33(10):1945 [18] Yang Y, Li X L, Yang R S, et al. Study on fractal characteristics and fracture mechanism of frozen rocks. Trans Beijing Inst Technol, 2020, 40(6): 632楊陽, 李祥龍, 楊仁樹, 等. 低溫巖石沖擊破碎分形特征與斷口形貌分析. 北京理工大學學報, 2020, 40(6):632 [19] Wang J G, Lei Z, Yang Y, et al. Strain rate effect of dynamic mechanical characteristics of saturated freezing granite. Chin J Undergr Space Eng, 2018, 14(5): 1292王建國, 雷振, 楊陽, 等. 飽水凍結花崗巖動態力學性狀的應變率效應. 地下空間與工程學報, 2018, 14(5):1292 [20] Zhou Y X, Xia K, Li X B, et al. Suggested methods for determining the dynamic strength parameters and mode-I fracture toughness of rock materials. Int J Rock Mech Min Sci, 2012, 49: 105 doi: 10.1016/j.ijrmms.2011.10.004 [21] Zhou Z L, Cai X, Chen L, et al. Influence of cyclic wetting and drying on physical and dynamic compressive properties of sandstone. Eng Geol, 2017, 220: 1 doi: 10.1016/j.enggeo.2017.01.017 [22] Ping Q, Luo X, Ma Q Y, et al. Broken energy dissipation characteristics of sandstone specimens under impact loads. Chin J Rock Mech Eng, 2015, 34(Suppl 2): 4197平琦, 駱軒, 馬芹永, 等. 沖擊載荷作用下砂巖試件破碎能耗特征. 巖石力學與工程學報, 2015, 34(增刊2): 4197 [23] Wen S, Zhao X W, Chang Y L, et al. Energy dissipation of dynamic failure of mixed rock specimens subject to SHPB compression. J Basic Sci Eng, 2021, 29(2): 483溫森, 趙現偉, 常玉林, 等. 基于SHPB的復合巖樣動態壓縮破壞能量耗散分析. 應用基礎與工程科學學報, 2021, 29(2):483 [24] Chen P Y, Zhao F J, Chen B, et al. Energy dissipation characteristics of prefabricated fractured rock under impact load. Miner Eng Res, 2021, 36(3): 17陳品崟, 趙伏軍, 陳彪, 等. 沖擊載荷下裂隙巖體破碎能量耗散特征. 礦業工程研究, 2021, 36(3):17 [25] Hu J, Gong F Q, Jia H Y. Research on mechanical and energy dissipation characteristics of red sandstone in SHPB compression test. Gold Sci Technol, 2020, 28(3): 411 doi: 10.11872/j.issn.1005-2518.2020.03.008胡健, 宮鳳強, 賈航宇. SHPB壓縮試驗中紅砂巖的力學與能量耗散特性研究. 黃金科學技術, 2020, 28(3):411 doi: 10.11872/j.issn.1005-2518.2020.03.008 [26] Wang M X, Wang H B, Zong Q. Experimental study on energy dissipation of mudstone in coal mine under im-pact loading. J China Coal Soc, 2019, 44(6): 1716王夢想, 汪海波, 宗琦. 沖擊荷載作用下煤礦泥巖能量耗散試驗研究. 煤炭學報, 2019, 44(6):1716 [27] Deng Y, Chen M, Jin Y, et al. Investigation of the dynamic characteristics and energy consumption for breaking rocks using the impact load. Petroleum Drill Tech, 2016, 44(3): 27鄧勇, 陳勉, 金衍, 等. 沖擊作用下巖石破碎的動力學特性及能耗特征研究. 石油鉆探技術, 2016, 44(3):27 -
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