CT visual quantitative characterization of meso-damage evolution of sandstone under freeze-thaw-loading synergistic effect
LIU Hui1，YANG Gengshe1，SHEN Yanjun2，YE Wanjun1，XI jiami1，JIN Long3，WEI Yao3，LI Borong3，LIU Shuai1
(1. College of Architecture and Civil Engineering，Xi?an University of Science and Technology，Xi?an，Shaanxi 710054，China；2. College of Geology and Environment，Xi?an University of Science and Technology，Xi?an，Shaanxi 710054，China；
3. CCCC First Highway Consultants Co.，Xi?an，Shaanxi 710065，China)
Abstract：Freeze-thaw cycle is an important factor leading to accelerated weathering failure of rock in cold regions. Fine cognition of damage evolution and internal mechanism of sandstone under the synergistic effect of freeze-thaw and load will have important guiding value for accurately understanding the whole process of damage characteristics of rock in cold regions. In this paper，the in-situ CT real-time scanning test of the sandstone damage process under the synergistic effect of freeze-thaw and load was carried out. Based on the interactive threshold segmentation of CT images and the reconstruction method of the three-dimensional pore structure model，the fine identification and visual quantitative characterization of pore(crack) evolution in freeze-thaw sandstone during uniaxial compression were realized. The lattice Boltzmann method was used to carry out the three-dimensional simulation of the connectivity change of sandstone pore structure under the synergistic effect of freeze-thaw and load，and the damage evolution law of sandstone mesostructure under the condition of freeze-thaw and load was clarified. The results show that：(1) the damage to freeze-thaw sandstone pore(fissure) structure has the characteristics of continuous evolution，but the damage evolution speed has a mutation phenomenon. Among them，the sharp increase of pore(fissure) volume can be used as a precursory failure signal of rock samples. (2) Different from conventional loading，uniaxial compression failure of sandstone after freeze-thaw changes from single through the shear plane to tensile-shear mixed failure，and the number of failure surfaces increases with the increase of freeze-thaw cycles. (3) The number of pore channels of rock samples increases with the increase of freeze-thaw cycles，and the gap connectivity tends to large；the maximum pore radius，pore number，maximum pore radius and porosity of the sample increase with the increase of load. The compression failure of sandstone under the synergistic effect of freeze-thaw and load is the product of the cumulative effect of continuous dislocation and expansion of pores and pores. (4) The internal pore(crack) structure of sandstone after loading failure in the low freezing-thawing cycle is mainly small pores，and the proportion of cracks is low；after high freeze-thaw cycles，the sandstone is dominated by the penetration crack propagation，and the porosity ratio decreases sharply. The freeze-thaw action promotes the transformation of the failure mode of the loaded sandstone from the continuous pore(crack) fracture mode to the multiple main cracks. (5) The connectivity of sandstone pore structure evolves along two paths of freeze-thaw and compression load，and its pore connectivity is mainly determined by the number of pores inside the rock sample. The first 10 freeze-thaw cycles are violent changes in pore structure expansion and connectivity.
[1] SATO A，HIRAKAWA Y，SUGAWARA K. Mixed mode crack propagation of homogenized cracks by the two-dimensional DDM analysis[J]. Construction and Building Materials，2001，15(5/6)：247–261.
[2] AL-SHAYEA N A. Crack propagation trajectories for rocks under mixed mode I-II fracture[J]. Engineering Geology，2005，81(1)：84–97.
[3] 谢和平，鞠 杨，黎立云，等. 岩体变形破坏过程的能量机制[J]. 岩石力学与工程学报，2008，27(9)：1 729–1 739.(XIE Heping，JU Yang，LI Liyun，et al. Energy mechanism of deformation and failure of rock masses[J]. Chinese Journal of Rock Mechanics and Engineering，2008，27(9)：1 729–1 739.(in Chinese))
[4] 孙 强，薛晓辉，朱术云，等. 岩石脆性破坏临界信息综合识别[J]. 固体力学学报，2013，34(3)：311–319.(SUN Qiang，XUE Xiaohui，ZHU Shuyun，et al. The identification method of critical information for rock brittle failure[J]. Chinese Journal of Solid Mechanics，2013，34(3)：311–319.(in Chinese))
[5] PARKA C H，BOBETB A. Crack initiation propagation and coalescence from frictional flaws in uniaxial compression[J]. Engineering Fracture Mechanics，2010，77(14)：2 727–2 748.
[6] CAMONESA L A M，EURÍPEDES D A V J，FIGUEIREDOB R P D，et al. Application of the discrete element method for modeling of rock crack propagation and coalescence in the step path failure mechanism[J]. Engineering Geology，2013，153(8)：80–94.
[7] 曾 鹏，刘阳军，纪洪广，等. 单轴压缩下粗砂岩临界破坏的多频段声发射耦合判据和前兆识别特征[J]. 岩土工程学报，2017，39(3)：509–517.(ZENG Peng，LIU Yangjun，JI Hongguang，et al. Coupling criteria and precursor identification characteristics of multi-band acoustic emission of gritstone fracture under uniaxial compression[J]. Chinese Journal of Geotechnical Engineering，2017，39(3)：509–517.(in Chinese))
[8] 付 斌，周宗红，王海泉，等. 大理岩单轴循环加卸载破坏声发射先兆信息研究[J]. 煤炭学报，2016，41(8)：1 946–1 953.(FU Bin，ZHOU Zonghong，WANG Haiquan，et al. Precursor information study on acoustic emission characteristics of marble under uniaxial cyclic loading-unloading[J]. Journal of China Coal Society，2016，41(8)：1 946–1 953.(in Chinese))
[9] 李德春，葛宝堂，舒继森. 岩体破坏过程中的电阻率变化试验[J]. 中国矿业大学学报，1999，28(5)：491–493.(LI Dechun，GE Baotang，SHU Jisen. Experimental study on resistivity change during rock mass failure process[J]. Journal of China University of Mining and Technology，1999，28(5)：491–493.(in Chinese))
[10] 李夕兵，翁 磊，谢晓锋，等.动静载荷作用下含孔洞硬岩损伤演化的核磁共振特性试验研究[J]. 岩石力学与工程学报，2015，34(10)：1 985–1 993.(LI Xibing，WENG Lei，XIE Xiaofeng，et al. Study on the degradation of hard rock with a pre-existing opening under static-dynamic loadings using nuclear magnetic resonance technique[J]. Chinese Journal of Rock Mechanics and Engineering，2015，34(10)：1 985–1 993.(in Chinese))
[11] 张庆贺，陈 晨，袁 亮，等. 基于DIC和YOLO算法的复杂裂隙岩石破坏过程动态裂隙早期智能识别[J]. 煤炭学报，2022，47(3)：1 208–1 219.(ZHANG Qinghe，CHEN Chen，YUAN Liang，et al. Early and intelligent recognition of dynamic cracks during damage of complex fractured rock masses based on DIC and YOLO algorithms[J]. Journal of China Coal Society，2022，47(3)：1 208–1 219.(in Chinese))
[12] 张 军，艾 池，李玉伟，等. 基于岩石破坏全过程能量演化的脆性评价指数[J]. 岩石力学与工程学报，2017，36(6)：1 326–1 340. (ZHANG Jun，AI Chi，LI Yuwei，et al. Brittleness evaluation index based on energy variation in the whole process of rock failure[J]. Chinese Journal of Rock Mechanics and Engineering，2017，36(6)：1 326–1 340.(in Chinese))
[13] 林大超，徐 谦，王仲琦，等. 岩石压缩破坏强度的一种理论估值方法[J]. 岩石力学与工程学报，2021，40(增1)：2 603–2 612.(LIN Dachao，XU Qian，WANG Zhongqi，et al.Theoretical approach to estimation of the rock failure strength under complex compression[J]. Chinese Journal of Rock Mechanics and Engineering，2021，40(Supp.1)：2 603–2 612.(in Chinese))
[14] 张开雨，夏开文，刘 丰. 基于Voronoi多边形离散的DDA方法模拟岩石破坏[J]. 岩石力学与工程学报，2021，40(4)：725–738. (ZHANG Kaiyu，XIA Kaiwen，LIU Feng，Simulation of rock failure by Voronoi-based discontinuous deformation analysis[J]. Chinese Journal of Rock Mechanics and Engineering，2021，40(4)：725–738.(in Chinese))
[15] 周火明，杨 宇，张宜虎. 多裂纹岩石单轴压缩渐进破坏过程精细测试[J]. 岩石力学与工程学报，2010，29(3)：465–470.(ZHOU Huoming，YANG Yu，ZHANG Yihu. Fine test on progressive fracturing process of multi-crack rock samples under uniaxial compression[J]. Chinese Journal of Rock Mechanics and Engineering，2010，29(3)：465–470.(in Chinese))
[16] 李树春，许 江，杨春和，等. 循环荷载下岩石损伤的CT细观试验研究[J]. 岩石力学与工程学报，2009，28(8)：1 604–1 609.(LI Shuchun，XU Jiang，YANG Chunhe，et al. Study of CT meso-experiment of rock damage under cyclic load[J]. Chinese Journal of Rock Mechanics and Engineering，2009，28(8)：1 604–1 609.(in Chinese))
[17] 杨更社，魏 尧，申艳军，等. 冻结饱和砂岩三轴压缩力学特性及强度预测模型研究[J]. 岩石力学与工程学报，2019，38(4)：683–694.(YANG Gengshe，WEI Yao，SHEN Yanjun，et al. Mechanical behavior and strength forecast model of frozen saturated sandstone under triaxial compression[J]. Chinese Journal of Rock Mechanics and Engineering，2019，38(4)：683–694.(in Chinese))
[18] 杨更社，刘 慧. 基于CT图像处理的冻结岩石细观结构及损伤力学特性[M]. 北京：科学出版社，2016：111–116.(YANG Gengshe，LIU Hui. Microstructure and damage mechanical characteristics of frozen rock based on CT image processing[M]. Beijing：Science Press，2016：111–116.(in Chinese))
[19] 汤明高，许 强，邓文锋，等. 冻融及加卸荷条件下川藏铁路典型岩石力学特性的劣化规律[J]. 地球科学，2022，47(6)：1 917–1 931. (TANG Minggao，XU Qiang，DENG Wenfeng，et al. The degradation law of mechanical properties of typical rock in Sichuan-Tibet Railway under freeze-thaw and unloading conditions[J]. Earth Science，2022，47(6)：1 917–1 931.(in Chinese))
[20] 贺晶晶，师俊平. 冻融后不同含水状态砂岩的剪切破坏特性[J]. 岩石力学与工程学报，2018，37(6)：1 350–1 358.(HE Jingjing，SHI Junping. Shear failure properties of sandstone with different moisture contents after cyclic freezing-thawing[J]. Chinese Journal of Rock Mechanics and Engineering，2018，37(6)：1 350–1 358.(in Chinese))
[21] 王乐华，姜照容，李建林，等. 冻融循环条件下层理砂岩卸荷力学特性试验研究[J]. 冰川冻土，2016，38(4)：1 052–1 058.(WANG Lehua，JIANG Zhaorong，LI Jianlin，et al．The bedding sandstone unloading mechanical properties experimental study in the freeze-thaw cycle conditions[J]. Journal of Glaciology and Geocryology，2016，38(4)：1 052–1 058.(in Chinese))
[22] 乔 趁，李长洪，王 宇，等. 冻融循环作用下中部锁固岩桥破坏试验研究[J]. 岩石力学与工程学报，2020，39(6)：1 094–1 103. (QIAO Chen，LI Changhong，WANG Yu，et al. Experimental study on failure of central rock bridge under freeze-thaw cycle[J]. Chinese Journal of Rock Mechanics and Engineering，2020，39(6)：1 094–1 103.(in Chinese))
[23] 李 平，唐旭海，刘泉声，等. 双裂隙类砂岩冻胀断裂特征与强度损失研究[J]. 岩石力学与工程学报，2020，39(1)：115–125.(LI Ping，TANG Xuhai，LIU Quansheng，et al. Experimental study on fracture characteristics and strength loss of intermittent fractured quasi-sandstone under freezing and thawing[J]. Chinese Journal of Chinese Journal of Rock Mechanics and Engineering，2020，39(1)：115–125.(in Chinese))
[24] 黄诗冰，刘泉声，刘艳章，等. 低温热力耦合下岩体椭圆孔(裂)隙中冻胀力与冻胀开裂特征研究[J]. 岩土工程学报，2018，40(3)：459–467.(HUANG Shibing，LIU Quansheng，LIU Yanzhang，et al. Frost heaving pressure and characteristics of frost cracking in elliptical cavity(crack) of rock mass under coupled thermal-mechanical condition at low temperature[J]. Chinese Journal of Geotechnical Engineering，2018，40(3)：459–467.(in Chinese))
[25] 刘 慧，蔺江昊，杨更社，等. 冻融循环作用下砂岩受拉损伤特性的声发射试验[J]. 采矿与安全工程学报，2020，38(1)：1–11.(LIU Hui，LIN Jianghao，YANG Gengshe，et al. Acoustic emission test on tensile damage characteristics of sandstone under freeze-thaw cycle[J]. Chinese Journal of Mining and Safety Engineering，2020，38(1)：1–11.(in Chinese))
[26] 吴 琳，李海燕. 面向生物医学图像的交互式分割算法[J]. 计算机工程，2010，36(16)：208–209.(WU Lin，LI Haiyan Interactive segmentation algorithm for bio-medicine image[J]. Computer Engineering，2010，36(16)：208–209.(in Chinese))
[27] AN H Y，ZHANG C H，MEND J P，et al. Analytical solution of Axi-symmetrical Lattice boltzmann model for cylindrical couette flows[J]. Physica A：statistical mechanics and its applications，2011，391(1/2)：8–14.
[28] 何雅玲，王 勇，李 庆. 格子Boltzmann方法的理论及应用[M]. 北京：科学出版社，2009：104–110.(HE Yaling，WANG Yong，LI Qing. The theory and application of lattice Boltzmann method[M]. Beijing：Science Press，2009：104–110.(in Chinese))
[29] MCNAMARA G R，ZANETTI G. Use of the Boltzmann equation to simulate lattice automata[J]. Physical Review Letters，1988，61(20)：2 332–2 335.
2023, Vol. 42 
