~陕西省府谷县地处黄河晋陕峡谷最北端，经常在冻融期发生岩质斜坡灾害，给区内社会经济发展造成重要影响，因此，开展冻融循环对岩土体物理力学特性影响的试验研究及其损伤机特性分析具有重要的理论与实际意义。本文以府谷县境内三叠系砂岩为研究对象，借助于试验测试与分析，开展了冻融循环温度与冻融次数影响下的砂岩宏微观物理力学特性试验研究，分析了砂岩在不同冻融循环作用后的损伤演化特征。主要研究成果如下：
（1）通过砂岩在不同冻融温差、不同冻融循环次数后的物理特性试验测试和分析，发现砂岩的纵波波速、电阻率均随冻融循环次数的增大而减小；砂岩饱和质量、核磁T2谱分布、核磁峰面积以及孔隙度均随冻融循环次数的增大而增大。
（2）通过砂岩在-20~20℃冻融循环温度、30次冻融循环次数后的单轴压缩试验和巴西劈裂试验测试分析。发现砂岩的饱和单轴抗压强度、抗拉强度和弹性模量均随着冻融循环次数的增加而逐渐减小；峰值应变随着冻融循环次数的增加先增大后减小。
（3）根据岩石力学损伤理论原理，分别从砂岩物理特性和力学特性角度定义砂岩冻融损伤劣化程度评价指标，建立损伤变量，研究了砂岩的物理力学特性与冻融循环次数的关系。研究结果表明：砂岩密度损伤变量、纵波波速损伤变量、电阻率损伤变量、核磁共振损伤变量、抗压强度损伤变量、抗拉强度损伤变量以及抗剪强度损伤变量与冻融循环次数均满足指数函数关系；砂岩物理力学特性的损伤特征与冻融循环次数间存在定量化关系，随着冻融循环次数的增大，损伤变量值逐渐增大，即砂岩受到的损伤程度持续增大。
 

~The Fugu district, Shaanxi province, is located at the north in Jinshan gorge area of the Yellow River. Geological hazards tend to happen in the slope in that place, which has resulted in severe influences to the economic development. Therefore, it is of great theoretical and practical significance to carry out experiments to study the effect of freeze-thaw cycle on the physical and mechanical properties of rock mass in this district and its damage mechanism. In this paper, the Triassic sandstone in the Fugu district was as the study object, and the macro-microphysical and mechanical properties of the sandstone under the influence of freeze-thaw cycle with different temperatures and frequencies were carried out. Based those experiments, the damage evolution characteristics of the sandstone was analyzed. The main research results are as follows:
(1) Based in the tests of the physical properties of the sandstone at different experimental conditions, the longitudinal wave velocity and resistivity decreased with the increase of the freeze-thaw cycle frequencies, but increased for the saturation mass, nuclear magnetic T2 spectrum distribution, area of nuclear magnetic peak, and porosity.
(2) In terms of the results of uniaxial compression tests and Brazilian cleavage tests at conditions of after 30 freeze-thaw cycles at -20~20 °C, the sandstone’ uniaxial compressive strength, peak tensile strength, and elastic modulus decreased when the freeze-thaw cycle frequencies increased, while the peak strain increased first and then decreased.
(3) According to the damage theory of rock mechanics, the relation between the physical and mechanical properties of the sandstone was studied, which was building on the definition of evaluation index of deterioration degree and the establishment of the damage variables. An exponential relationship was shown between the freeze-thaw cycle frequencies and each damage variable of the density, p-wave velocity, resistivity, nuclear magnetic resonance, compressive strength, tensile strength, and shear strength. The value of these damage variables increased with the increase of the freeze-thaw cycle frequencies, namely an intensify of the damage degree of the sandstone.
 

[1] 何国梁, 张磊, 吴刚. 循环冻融条件下岩石物理特性的试验研究[J]. 岩土力学, 2004, 1(2): 52-56.

[2] 周科平, 李杰林, 许玉娟, 等. 冻融循环条件下岩石核磁共振特性的试验研究[J]. 岩石力学与工程学报, 2012, 31(4): 731-737.

[3] 李建林. 岩石力学[M]. 重庆: 重庆大学出版社, 2014.

[4] 杨更社, 张全胜, 蒲毅彬. 冻结温度对岩石细观损伤扩展特性影响研究初探[J]. 岩土力学, 2004, (9): 1409-1412.

[5] 路亚妮, 李新平, 韩燕华. 各向异性砂岩冻融力学特性研究[J]. 冰川冻土, 2020, 42(3): 889-898.

[6] HEUZE F E. High-temperature mechanical, physical and thermal properties of granitic rocks—a review[J]. Int J Rock Mech Min Sci Geamech Abstr, 1983, 20(1): 3-10

[7] ROAL M D, LOPEZ F, ESTEBAN F J, et al. Ultrasonic study of alteration processes in granites caused by freezing and thawing[C] proceedings of the IEEE Ultrasonics Symposium, Netherlands, institute of electrical and electrinics engineerings, 2005, 1051-1057.

[8] MARTíNEZ J, BENAVENTE D, GóMEZ-HERAS M, et al. Non-linear decay of building stones during freeze–thaw weathering processes[J] Construction and Building Materials. 2013, 38(1): 443-454.

[9] HAN T, BEST A I, SOTHCOTT J, et al. Relationships among low frequency (2Hz) electrical resistivity, porosity, clay content and permeability in reservoir sandstones[J]. Journal of Applied Geophysics, 2015, 112(1): 279-289.

[10] HERMAN R. An introduction to electrical resistivity in geophysics[J]. American Journal of Physics, 2001, 69(9): 943-952.

[11] SAMOUëLIAN A, COUSIN I, TABBAGH A, et al. Electrical resistivity survey in soil science: a review[J]. Soil and Tillage Research, 2005, 83(2): 173-193.

[12] SONDERGELD C H, RAI C S. Velocity and resistivity changes during freeze-thaw cycles in Berea sandstone[J]. Geophysics, 2007, 72(2): 99-105.

[13] ABU-HASSANEIN ZEYAD S, BENSON CRAIG H, BLOTZ LISA R. Electrical Resistivity of Compacted Clays[J]. Journal of Geotechnical Engineering, 1996, 122(5): 397-406.

[14] SHANMUGAM J, MUTHIAH K, MOOKIAH M. Use of electrical resistivity method to quantify accumulated sediments in Wellington reservoir, India[J]. Geosciences Journal, 2022, 26(1): 141-149.

[15] ARCHIE G E. The Electrical Resistivity Log as an Aid in Determining Some Reservoir Characteristics[J]. Transactions of the AIME, 1942, 146(1): 54-62.

[16] 刘杰, 王飞, 杨渝南, 等. 冻融循环中低应力水平加卸载作用下砂岩物理特性研究[J]. 水利水电技术, 2016, 47(11): 129-135.

[17] 刘民安, 董亚萍, 李晨, 等. 冻融干湿循环条件下压砂砾石损伤过程[J]. 农业工程学报, 2021, 37(1): 176-187.

[18] 吴国鹏, 谌文武, 崔凯, 等. 冻融作用下全风化千枚岩力学性质研究[J]. 兰州大学学报(自然科学版), 2019, 55(3): 388-394.

[19] 吴国鹏, 谌文武, 崔凯, 等. 冻融和干湿作用下表生板岩的劣化行为与机制[J]. 中南大学学报(自然科学版), 2019, 50(6): 1392-1402.

[20] 贾海梁, 刘清秉, 项伟, 等. 冻融循环作用下饱和砂岩损伤扩展模型研究[J]. 岩石力学与工程学报, 2013, 32(S2): 3049-3055.

[21] 贾海梁, 王婷, 项伟, 等. 含水率对泥质粉砂岩物理力学性质影响的规律与机制[J]. 岩石力学与工程学报, 2018, 37(7): 1618-1628.

[22] 贾海梁, 项伟, 谭龙, 等. 砂岩冻融损伤机制的理论分析和试验验证[J]. 岩石力学与工程学报, 2016, 35(5): 879-895.

[23] 张慧梅, 杨更社. 冻融与荷载耦合作用下岩石损伤模型的研究[J]. 岩石力学与工程学报, 2010, 29(3): 471-476.

[24] 张慧梅, 杨更社. 冻融环境下红砂岩力学特性试验及损伤分析[J]. 力学与实践, 2013, 35(3): 57-61.

[25] 张慧梅, 张蒙军, 谢祥妙, 等. 冻融循环条件下红砂岩物理力学特性试验研究[J]. 太原理工大学学报, 2015, 46(1): 69-74.

[26] 苏伟. 冻融循环对岩石物理力学性质及边坡稳定性影响的研究[D]. 长沙: 长沙矿山研究院, 2012.

[27] 李杰林. 基于核磁共振技术的寒区岩石冻融损伤机理试验研究[D]. 长沙: 中南大学, 2012.

[28] 李杰林, 刘汉文. 冻融循环作用下砂岩孔隙体积变形模型的建立与分析[J]. 冰川冻土, 2018, 40(6): 1173-1180.

[29] 李杰林, 刘汉文, 周科平, 等. 冻融作用下岩石细观结构损伤的低场核磁共振研究[J]. 西安科技大学学报, 2018, 38(2): 266-272.

[30] 李杰林, 周科平, 柯波. 冻融后花岗岩孔隙发育特征与单轴抗压强度的关联分析[J]. 煤炭学报, 2015, 40(8): 1783-1789.

[31] 李杰林, 周科平, 张亚民, 等. 冻融循环条件下风化花岗岩物理特性的实验研究[J]. 中南大学学报(自然科学版), 2014, 45(3): 798-802.

[32] 李杰林, 朱龙胤, 周科平, 等. 冻融作用下砂岩孔隙结构损伤特征研究[J]. 岩土力学, 2019, 40(9): 3524-3532.

[33] 崔凯, 刘桂山, 吴国鹏, 等. 不同条件下贺兰口岩画载体岩石冻融损伤特征与机制研究[J]. 岩石力学与工程学报, 2019, 38(9): 1797-1808.

[34] WANG H W, HEARD H C. Prediction of elastic moduli via crack density in pressurized and thermally stressed rock[J]. J Geophy Res, 1985, 90(1): 342-350.

[35] CHEN Y-L, NI J, JIANG L-H, et al. Experimental study on mechanical properties of granite after freeze–thaw cycling[J]. Environmental Earth Sciences, 2014, 71(8): 3349-3354.

[36] MATSUOKA N. Mechanisms of rock breakdown by frost action: An experimental approach[J]. Cold Regions Science and Technology, 1990, 17(3): 253-270.

[37] NICHOLSON D T, NICHOLSON F H. Physical deterioration of sedimentary rocks subjected to experimental freeze–thaw weathering[J]. Earth Surface Processes and Landforms, 2000, 25(12): 1295-1307.

[38] PRICK A. Dilatometrical behaviour of porous calcareous rock samples subjected to freeze-thaw cycles[J]. CATENA, 1995, 25(1): 7-20.

[39] FAHEY B D. Frost action and hydration as rock weathering mechanisms on schist: A laboratory study[J]. Earth Surface Processes and Landforms, 1983, 8(6): 535-545.

[40] 赵涛, 杨更社, 任俊童, 等. 不同负温对冻结饱和砂岩力学特性的影响[J]. 西安科技大学学报, 2020, 40(6): 996-1002.

[41] 方云, 乔梁, 陈星, 等. 云冈石窟砂岩循环冻融试验研究[J]. 岩土力学, 2014, 35(9): 2433-2442.

[42] 陈有亮, 王朋, 张学伟, 等. 花岗岩在化学溶蚀和冻融循环后的力学性能试验研究[J]. 岩土工程学报, 2014, 36(12): 2226-2235.

[43] JIA H, ZI F, YANG G, et al. Influence of Pore Water (Ice) Content on the Strength and Deformability of Frozen Argillaceous Siltstone[J]. Rock Mechanics and Rock Engineering, 2020, 53(2): 967-974.

[44] LI Y, ZHAI Y, MENG F, et al. Study on the Influence of Freeze–Thaw Weathering on the Mechanical Properties of Huashan Granite Strength[J]. Rock Mechanics and Rock Engineering, 2021, 54(9): 4741-4753.

[45] CHEN T C, YEUNG M R, MORI N. Effect of water saturation on deterioration of welded tuff due to freeze-thaw action[J]. Cold Regions Science and Technology, 2004, 38(2): 127-136.

[46] GHOBADI M H, BABAZADEH R. Experimental Studies on the Effects of Cyclic Freezing–Thawing, Salt Crystallization, and Thermal Shock on the Physical and Mechanical Characteristics of Selected Sandstones[J]. Rock Mechanics and Rock Engineering, 2015, 48(3): 1001-1016.

[47] 王来贵, 丁盛鹏, 何慧娟, 等. 冻融循环作用下含结核砂岩风化特征实验研究[J]. 工程地质学报, 2018, 26(3): 611-619.

[48] 王鲁男, 尹晓萌, 韩杰, 等. 化学溶液与冻融循环作用下粉砂岩强度衰减及预测模型[J]. 中南大学学报(自然科学版), 2020, 51(8): 2361-2372.

[49] 刘泉声, 黄诗冰, 康永水, 等. 裂隙岩体冻融损伤研究进展与思考[J]. 岩石力学与工程学报, 2015, 34(3): 452-471.

[50] 刘泉声, 黄诗冰, 康永水, 等. 岩体冻融疲劳损伤模型与评价指标研究[J] 岩石力学与工程学报, 2015, 34(6): 1116-1127.

[51] 周科平, 许玉娟, 李杰林, 等. 冻融循环对风化花岗岩物理特性影响的实验研究[J]. 煤炭学报, 2012, 37(S1): 70-74.

[52] 周科平, 张亚民, 李杰林, 等. 冻融花岗岩细观损伤演化的核磁共振[J]. 中南大学学报(自然科学版), 2013, 44(8): 3384-3389.

[53] 贾海梁. 多孔岩石及裂隙岩体冻融损伤机制的理论模型和试验研究[D]. 北京: 中国地质大学, 2016.

[54] 任建喜, 孙杰龙, 张琨, 等. 富水砂层斜井冻结壁力学特性及温度场研究[J] 岩土力学, 2017, 38(5): 1405-1412.

[55] 任建喜, 王晓琳, 陈旭. 洛河组砂岩解冻后物理力学性质及破坏特征研究[J] 煤炭工程, 2021, 53(2): 153-158.

[56] 刘慧, 杨更社, 任建喜. 基于数字图像处理的冻融页岩温度场的数值分析方法[J] 岩石力学与工程学报, 2007, 1(8): 1678-1683.

[57] 杨更社, 申艳军, 贾海梁, 等. 冻融环境下岩体损伤力学特性多尺度研究及进展[J]. 岩石力学与工程学报, 2018, 37(3): 545-563.

[58] 申艳军, 杨更社, 荣腾龙, 等. 冻融循环作用下单裂隙类砂岩局部化损伤效应及端部断裂特性分析[J]. 岩石力学与工程学报, 2017, 36(3): 562-570.

[59] 申艳军, 杨更社, 王铭, 等. 冻融–周期荷载下单裂隙类砂岩损伤及断裂演化试验分析[J]. 岩石力学与工程学报, 2018, 37(3): 709-717.

[60] 高峰, 曹善鹏, 熊信, 等. 冻融循环作用下受荷青砂岩的脆性演化特征[J]. 岩土力学, 2020, 41(2): 445-452.

[61] 高峰, 熊信, 周科平, 等. 冻融循环作用下饱水砂岩的强度劣化模型[J]. 岩土力学, 2019, 40(3): 926-932.

[62] 丁自伟, 李小菲, 唐青豹, 等. 砂岩颗粒孔隙分布分形特征与强度相关性研究[J]. 岩石力学与工程学报, 2020, 39(9): 1787-1796.

[63] 王潇. 冻融循环条件下陕北府谷地区砂岩物理力学性质研究[D]. 西安: 西安科技大学, 2014.

[64] 马逢清. 冻融循环条件下府谷地区砂岩、泥岩物理性质及细观结构研究[D]. 西安: 西安科技大学, 2014.

[65] ONDRáŠIK M, KOPECKý M. Rock Pore Structure as Main Reason of Rock Deterioration[J]. Studia Geotechnica et Mechanica, 2014, 36(1): 79-88.

[66] VON HELMHOLTZ R. Untersuchungen über Dämpfe und Nebel, besonders über solche von Lösungen[J]. Annalen der Physik, 1886, 263(4): 508-543.

[67] 杜鹏, 姚燕, 王玲, 等. 基于冻融损伤的混凝土寿命预测研究进展[J] 长江科学院院报, 2014, 31(4): 77-84.

[68] 曹文贵, 张超, 贺敏, 等. 岩石孔隙变化及其变形全过程的统计损伤模拟方法[J] 湖南大学学报(自然科学版), 2017, 44(9): 100-106.

[69] 王超, 徐杨青, 高晓耕. 受压岩石的电阻率变化特征与煤矿采空区覆岩的损伤演化 [J] 煤炭工程, 2021, 53(2): 117-121.

[70] 郭耀, 李刚, 贾成艳, 等. 冰力学参数的超声波测试研究[J]. 极地研究, 2016, 28(1): 152-157.