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张站群, 蔚立元, 李光雷, 苏海健, 靖洪文. 化学腐蚀后灰岩动态拉伸力学特性试验研究[J]. 岩土工程学报, 2020, 42(6): 1151-1158. DOI: 10.11779/CJGE202006021
引用本文: 张站群, 蔚立元, 李光雷, 苏海健, 靖洪文. 化学腐蚀后灰岩动态拉伸力学特性试验研究[J]. 岩土工程学报, 2020, 42(6): 1151-1158. DOI: 10.11779/CJGE202006021
ZHANG Zhan-qun, YU Li-yuan, LI Guang-lei, SU Hai-jian, JING Hong-wen. Experimental research on dynamic tensile mechanics of limestone after chemical corrosion[J]. Chinese Journal of Geotechnical Engineering, 2020, 42(6): 1151-1158. DOI: 10.11779/CJGE202006021
Citation: ZHANG Zhan-qun, YU Li-yuan, LI Guang-lei, SU Hai-jian, JING Hong-wen. Experimental research on dynamic tensile mechanics of limestone after chemical corrosion[J]. Chinese Journal of Geotechnical Engineering, 2020, 42(6): 1151-1158. DOI: 10.11779/CJGE202006021

化学腐蚀后灰岩动态拉伸力学特性试验研究

Experimental research on dynamic tensile mechanics of limestone after chemical corrosion

  • 摘要: 为探究化学腐蚀后灰岩的动态拉伸力学特性,本次试验配制了pH=3的NaCl和KHSO4混合溶液对灰岩试样进行不同时间的腐蚀(腐蚀时间分别为30,60,90,120和150 d)。通过核磁共振测试获得腐蚀后试样的T2谱图及孔隙率,并利用分离式霍普金斯压杆对腐蚀后灰岩试样进行动态拉伸试验,最后得到了灰岩动态拉伸强度以及能量耗散等随腐蚀损伤度的变化规律。此外,借助扫描电镜和X射线荧光光谱分析获得各腐蚀阶段试样的SEM图像和矿物成分含量。结果表明:随腐蚀时间增加,灰岩孔隙率从自然状态下0.32%增大到5.32%(150 d),腐蚀损伤度同步增大;动态抗拉强度劣化程度为32.52%,并可根据下降速率区分为2个阶段;耗散能和透射能分别展现出两阶段减小变化趋势,表现出明显的损伤度相关性;化学腐蚀后灰岩的破坏模式由典型的劈裂破坏向拉剪混合、剪切破坏过渡,直至粉末块状破坏。宏观力学性质与试样内部微观结构损伤有着密不可分的关联性,研究结果可为地下工程的设计施工提供借鉴。

     

    Abstract: To investigate the dynamic tensile mechanical properties of limestone corroded in the chemical environment, the mixed solution of NaCl and KHSO4 with pH=3 was prepared to corrode limestone samples for different corrosion time, i.e. 30 days, 60 days, 90 days, 120 days and 150 days, respectively. The T2 spectra and porosity of the corroded limestone samples were obtained by nuclear magnetic resonance (NMR) test, and the dynamic tensile test was carried out on corroded limestone samples by using the separated Hopkins compression bar (SHPB). Finally, the variation law of dynamic tensile strength and energy dissipation with corrosion damage degree of limestone was obtained. In addition, microscopic images and mineral contents of samples at different corrosion stages were analyzed by scanning electron microscopy (SEM) and X-ray fluorescence spectrometry (XRF). The result shows that, after being corroded for 150d, the porosity of limestone rises from 0.32% to 5.32% and the corrosion damage degree increases.The deterioration of dynamic tensile strength can be divided into two stages by the slope, with the total decrease extent of 32.52%. Dissipative energy and transmission energy exhibit two-stage decreasing trend and distinct correlation to damage degree. The failure mode evolution of limestone after chemical corrosion changes from the typical splitting failure to the tensile-shear, shear failure and ultimate powders failure. There is a distinct relationship between the macro-mechanical properties and the micro-structure damage of specimens. The research results can provide references for the design and construction of underground engineering.

     

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