水、盐含量对黄土地球物理表现的影响是近些年来工程地质学、土壤学、能源学、电气安全学及地热资源开发领域的研究热点，国内外众多学者围绕水、盐耦合作用下的地球物理表现进行了大量的试验研究。然而，目前关于土体的水、盐含量与电阻率及热参数的关系却很少被提及，相关研究也不够系统。泾阳南塬系渭北黄土台塬，随着该地区农业的发展，大量化学肥料在农耕活动中被使用，随着漫灌的进行，肥料中的各种盐分被灌溉水溶解，入渗斜坡并发生迁移，最终在斜坡坡脚处积累，黄土中出现“析盐”现象。水、盐的作用会改变黄土的结构，进而对其力学性质造成影响。在这一过程中，黄土的地球物理表现会发生显著变化，尤其是电阻率和热参数。因此，查明黄土中电阻率、热参数随水、盐含量变化的规律，对土体的水盐运移规律和地球物理表现研究具有重要意义。

为了探明黄土中水、盐含量与电阻率和热参数的关系，拟通过电阻率测试试验，得到水、盐含量与电阻率间的变化关系；进一步利用单轴压缩试验与电阻率测试试验相结合，得到在黄土受压变形过程中的电阻率变化规律；最后通过热参数测试试验，得到水、盐含量与热导率、比热容及热扩散率间的变化关系。具体有以下认识：

（1）电能传导遵循优势路径原则。随着黄土试样中含水量的增加，电能传导通道从固-液混合传导变为液-液传导，电阻率下降；随着含盐量的增加，试样中游离态的Na⁺和Cl^-增多，试样的导电性增强，电阻率下降；测试频率会使测试层中游离态的Na⁺、Cl^-和H₂O分子产生定向排列和电离极化现象，随着测试频率的增大，土体颗粒双电层中游离态的离子会被逐渐释放出来，使试样的导电性增强，电阻率下降；

（2）当黄土试样的应变较小时，黄土结构挤密，孔隙逐渐闭合，电阻率略有上升；随着应变逐渐增大，试样中产生轴向微裂隙，孔隙水会进入微裂隙中，试样导电性增强，电阻率降低；随着应变进一步增大，试样中轴向的微裂隙逐渐扩张并形成横向连通，试样导电性增强，电阻率降低；当试样剪切破坏时，其中的微裂隙贯通，电能传导基本以孔隙水为主，电阻率变化幅度极小；

（3）随着含水量的增加，黄土试样中会产生“液桥”现象，热能传导路径从固-气传导为主变为了液-液传导为主，热导率总体呈现上升趋势；随着含盐量的增加，试样中会出现“压缩双电层”和“絮凝”现象，热导率总体上呈现为先上升后下降趋势；

（4）在低于塑限含水量的条件下，随着含水量的增加，孔隙水进入孔隙占据了空气的位置，黄土试样的比热容快速上升；当含水量达到塑限之后，随着含水量的增加，孔隙水彼此连通，试样的比热容快速上升；盐含量对比热容的影响较小。

（5）当含水量在8~16%时，试样的热扩散率整体变化较小；当含水量大于16%后，热扩散率有一定程度的下降；当含盐量在0~6%时，试样的热扩散率总体呈下降趋势。

In recent years, the influence of water and salt content on loess geophysical performance has become a research hotspot in the fields of engineering geology, soil science, energy science, electrical safety and geothermal resource development. Many scholars at home and abroad have conducted a large number of experimental studies on the geophysical performance under the coupling effect of water and salt. However, the relationship between water and salt content of soil and resistivity and thermal parameters has rarely been mentioned, and the relevant research is not systematic enough. With the development of agriculture in this area, a large number of chemical fertilizers were used in farming activities. With the progress of flood irrigation, various salts in fertilizers were dissolved by irrigation water, infiltrated into slopes and migrated, and finally accumulated at the foot of slopes, resulting in "salt evolution" in loess. The action of water and salt will change the structure of loess and then affect its mechanical properties. During this process, the geophysical characteristics of loess, especially resistivity and thermal parameters, will change significantly. Therefore, it is of great significance to find out the law of resistivity and thermal parameters changing with water and salt content in loess, and to study the law of water and salt migration and geophysical behavior of soil.

In order to explore the relationship between water and salt content in loess and resistivity and thermal parameters, it is planned to obtain the relationship between water and salt content and resistivity through resistivity test. Furthermore, uniaxial compression test and resistivity test were combined to obtain the resistivity variation rule during the compression deformation of loess. Finally, the relationship between water and salt content and thermal conductivity, specific heat capacity and thermal diffusivity is obtained through thermal parameter test. The specific conclusions are as follows:

(1) Electric energy conduction follows the principle of dominant path. With the increase of water content in loess samples, the power conduction channel changes from solid-liquid mixed conduction to liquid-liquid conduction, and the resistivity decreases. With the increase of salt content, the free state Na⁺ and Cl^- in the sample increase, and the electrical conductivity of the sample increases, but the resistivity decreases. The free Na⁺, Cl^- and H₂O molecules in the test layer are oriented and ionized. With the increase of the test frequency, the free ions in the double electric layer of soil particles are gradually released, which makes the electrical conductivity of the sample enhanced and the resistivity decreased.

(2) When the strain of loess sample is small, the loess structure is compact, the pores gradually close, and the resistivity rises slightly; As the strain gradually increases, axial micro-cracks occur in the sample, and liquid will enter into the micro-cracks. The conductivity of the sample increases and the resistivity decreases. With the further increase of strain, the axial micro-cracks in the sample gradually expand and form transverse connectivity, and the electrical conductivity of the sample increases, but the resistivity decreases. When the sample is broken by shear, the microcracks are connected, and the electric energy conduction is mainly pore water, and the resistivity variation is very small.

(3) With the increase of water content, "liquid bridge" phenomenon occurs in loess samples, and the heat conduction path changes from solid-gas conduction to liquid-liquid conduction, and the thermal conductivity generally presents an upward trend. With the increase of salt content, the phenomenon of "compressed double electric layer" and "flocculation" will appear in the samples, and the thermal conductivity will increase first and then decrease.

(4) When the water content is lower than the plastic limit, with the increase of water content, water enters the pores and occupies the position of air, and the specific heat capacity of loess samples rises rapidly. When the water content reaches the plastic limit, the pore water is connected with each other with the increase of water content, and the specific heat capacity of the sample rises rapidly. Salt content has little effect on specific heat capacity.

(5) When the moisture content is 8~16%, the thermal diffusivity changes little. When the water content is more than 16%, the thermal diffusivity decreases to a certain extent. When the salt content is 0~6%, the thermal diffusivity of the samples decreases.

[1] 中国土壤学会. 土壤农业化学常规分析方法 [M]. 土壤农业化学常规分析方法, 1983.

[2] 杜宜臻, 李韧, 吴通华, 等. 土壤热导率的研究现状及其进展 [J]. 冰川冻土, 2015, 37(4):1067-1074.

[3] 谢瑞珍, 韩鹏举, 白晓红, 等. 典型砂土盐渍土的电化学特性及其腐蚀性研究 [J]. 太原理工大学学报, 2019, 50(2): 212-221.

[4] Datsios Z G, Mikropoulos P N, Karakousis I. Laboratory characterization and modeling of DC electrical resistivity of sandy soil with variable water resistivity and content [J]. IEEE Transactions on Dielectrics Electrical Insulation, 2017, 24(5): 3063-3072.

[5] Rafaela, Cardoso, Ana, et al. Study of the electrical resistivity of compacted kaolin based on water potential [J]. Engineering Geology, 2017, 226:1-11.

[6] 罗述伟. 钠盐盐渍土的电阻率特性分析 [D]; 陕西省. 西北农林科技大学, 2019.

[7] A M F, A T M, B H H, et al. The micro-structures of clay given by resistivity measurements [J]. Engineering Geology, 1999, 54(1–2): 43-53.

[8] 郭丽. 冻融循环条件下水泥固化土的电阻率与强度特性试验研究 [D]; 四川省. 西南科技大学, 2019.

[9] 查甫生, 刘松玉. 土的电阻率理论及其应用探讨 [J]. 工程勘察, 2006, (5): 10-15,44.

[10] 霍海峰, 王文博. 盐溶液对于水泥土抗压强度和电阻率的影响 [J]. 中国民航大学学报, 2017, 35(6): 52-56..

[11] Abu-Hassanein Z S, Benson C H, Blotz L R. Electrical resistivity of compacted clays [J]. Journal of Geotechnical Engineering, 1996, 122(5): 397-406.

[12] 储亚, 刘松玉, 蔡国军, 等. 岩土体电阻率模型研究进展 [J]. 南京工程学院学报：自然科学版, 2017, 15(2): 1-9.

[13] 王雅君, 通瑞生, 薛维俊. 对称四极电测深法在测量场地浅部地层土壤电阻率中的应用 [J]. 内蒙古电力技术, 2020, 38(3): 62-66.

[14] 揣国权, 黄振航, 宫奇伟, 等. 土壤电阻率季节变化与气象因素关系分析 [J]. 气象与减灾研究, 2020, 43(1): 67-72.

[15] Munoz-Castelblanco J A, Pereira J M, Delage P, et al. The influence of changes in water content on the electrical resistivity of a natural unsaturated loess [J]. Fuel, 2012, 35(1): 11-17.

[16] Bery A A, Ismail N E H. Empirical Correlation Between Electrical Resistivity and Engineering Properties of Soils [J]. Soil Mechanics Foundation Engineering, 2018, 54(6): 425-429.

[17] 刘寅颖, 童跃光. 某高土壤电阻率的建筑群接地系统浅析 [J]. 智能建筑电气技术, 2019, 13(6): 46-50.

[18] 易少凤, 刘诗武. 干燥砂卵石土壤电阻率测量接触电阻问题研究 [J]. 电力勘测设计,2015(z1):96-98.

[19] 于小军, 刘松玉. 电阻率指标在膨胀土结构研究中的应用探讨 [J]. 岩土工程学报, 2004, 26(3): 393-396.

[20] 刘春泉, 厚军学, 张伟. 宁夏土壤电阻率时空分布观测试验 [J]. 气象科技, 2008,36(4):474-479.

[21] 徐霞, 刘熙, 刘刚, 等. 典型地区土壤电阻率的时空特性研究 [J]. 水电能源科学, 2017, 35(2): 204-207,169.

[22] 曹晓斌, 吴广宁, 付龙海, 等. 温度对土壤电阻率影响的研究 [J]. 电工技术学报, 2007, 22(9): 1-6.

[23] 冯旭宇, 刘晓东, 石湘波, 等. 不同覆盖类型土壤电阻率影响因子及其PLS和BP模型的预测研究 [J]. 现代农业科技, 2017, (9): 198-201,208.

[24] 孙宇瑞. 土壤含水率和盐分对土壤电导率的影响 [J]. 中国农业大学学报, 2000, 5(4): 39-41.

[25] 张永双, 曲永新. 黄土高原马兰黄土粘土矿物的定量研究 [J]. 地质论评, 2004, 50(5): 530-537.

[26] 吴芝兰, 曲永新. 微团聚体分析在工程地质研究中的应用 [J]. 工程地质学报, 1997, 5(3): 282-288.

[27] 刘晓京, 陈新建, 冯满, 等. 可溶盐对原状黄土强度影响的试验研究 [C] //2018年全国工程地质学术年会论文集. 2018:652-656.

[28] 韩鹏举, 白晓红, 赵永强, 等. Mg2+和SO42-相互影响对水泥土强度影响的试验研究 [J]. 岩土工程学报, 2009, 31(1): 72-76.

[29] 何斌, 韩鹏举, 白晓红. NaCl污染土中含水量和电阻率对腐蚀速率的影响 [J]. 科学技术与工程, 2014, 14(33): 318-321,326.

[30] 董晓强, 白晓红, 赵永强, 等. NaOH污染下水泥土的电阻率变化研究 [J]. 岩土工程学报, 2007, 29(11): 1715-1719.

[31] 董晓强, 白晓红, 赵永强, 等. 电阻率法对硫酸影响水泥土力学性能的初步研究 [J]. 硅酸盐通报, 2008, 27(6): 1212-1216.

[32] 王帅, 韩鹏举. 粉质黏土电化学阻抗特性 [J]. 中国科技论文, 2015, 10(18): 2169-2173.

[33] 张凯信, 韩鹏举, 雷钰, 等. 高岭土电化学阻抗谱与抗剪强度的试验研究 [J]. 非金属矿, 2019, 42(3): 62-65.

[34] 许书强, 谢瑞珍, 韩鹏举. 氯化钠盐渍砂土电化学特性的试验研究 [J]. 科学技术与工程, 2018, 18(19): 100-105.

[35] 张亚芬, 韩鹏举, 何斌. 砂土的电化学阻抗特性及其试验研究 [J]. 太原理工大学学报, 2017, 48(1): 55-61.

[36] 黄新恩, 董晓强, 曾滟捷, 等. 水泥土受压过程中电阻率的变化研究 [J]. 太原理工大学学报, 2010, 41(3): 269-271.

[37] 赵永强, 白晓红, 韩鹏举, 等. 土体污染对水泥土力学性质的影响 [J]. 天津大学学报:自然科学与工程技术版, 2008, 41(001): 72-77.

[38] Gamage D, Biswas A, Strachan I B. Spatial variability of soil thermal properties and their relationships with physical properties at field scale [J]. Soil Tillage Research, 2019, 193: 50-58.

[39] Bo C, Fen Z, Huilong M, et al. State of the Art Review Soil Thermal Conductivity Studies [J]. Soil Engineering and Foundation, 2019, 33(5): 575-578.

[40] Yizhen D U, Ren L I, Tonghua W U, et al. Study of soil thermal conductivity: research status and advances [J]. Journal of Glaciology Geocryology, 2015,37(4):1067-1074.

[41] Rees S W, Ad Jali M H, Zhou Z, et al. Ground heat transfer effects on the thermal performance of earth-contact structures [J]. Renewable Sustainable Energy Reviews, 2000, 4(3): 213-265.

[42] Smits K M, Kirby E, Massman W J, et al. Experimental and Modeling Study of Forest Fire Effect on Soil Thermal Conductivity [J]. Soil Circle, 2016, 26(4): 462-473.

[43] 于明志, 曹西忠, 王善明, 等. 水分含量对土壤导热系数的影响及机理 [J]. 山东建筑大学学报, 2012, 27(2): 152-154,159.

[44] 张飞. 含水率和低温对黄土热物理参数影响性研究 [J]. 铁道工程学报, 2019, 36(11): 57-61.

[45] 李仁杰, 王旭, 张延杰, 等. 大气作用下浅层非饱和黄土温度变化及其影响因素研究 [J]. 工程地质学报, 2019,27(4):766-774.

[46] 周殷康, 阎长虹, 谢胜华, 等. 基于细观模拟的软土导热系数数值预测模型 [J]. 工程地质学报, 2019, 27(5): 1070-1077.

[47] 张立新, 陶兆祥. 氯化钠的掺入对冻土基本热学性质的影响 [J]. 冰川冻土, 1995, (1):49-53.

[48] 袁红，李斌. 硫酸盐渍土起胀含盐量及容许含盐量的研究 [J]. 中国公路学报, 1995, (3): 10-14.

[49] 邓友生, 何平, 周成林. 含盐土导热系数的试验研究 [J]. 冰川冻土, 2004, 26(3): 319-323.

[50] 刘东林, 李义曼, 庞忠和, 等. 碳酸盐岩热储对湖水回灌的响应 [J]. 工程地质学报, 2019, 27(1): 178-183.

[51] 董西好, 叶万军, 杨更社, 等. 温度对黄土热参数影响的试验研究 [J]. 岩土力学, 2017, 38(10): 2888-2894,2900.

[52] 叶万军, 董西好, 杨更社, 等. 含水率和干密度对黄土热参数影响的试验研究 [J]. 岩土力学, 2017, 38(3): 656-662.

[53] 苏天明, 刘彤, 李晓昭, 等. 南京地区土体热物理性质测试与分析 [J]. 岩石力学与工程学报, 2006, 25(6): 1278-1283.

[54] 袁巧霞. 温度和含水率对土壤比热容影响的神经网络预测 [J]. 农业机械学报, 2008,39(5):108-111.

[55] 涂新斌, 戴福初. 土体一维传热方程解析解及热扩散系数测定 [J]. 岩土工程学报, 2008, 30(5): 652-657.

[56] 苏占东, 孙进忠, 周富彪, 等. 风积沙改性土热物理性质的测试与分析 [J]. 水利水电技术, 2019,50(7):153-159.

[57] 安可栋, 王文科, 王周峰, 等. 风积沙热参数计算及其与含水率关系研究 [J]. 水文地质工程地质, 2015, 42(5): 129-133.

[58] 战丽媛, 白子卉, 解影, 等. 日光温室深埋秸秆不同灌水下限对土壤热扩散率的影响 [J]. 土壤通报, 2019, 50(5): 1145-1150.

[59] 周亚, 高晓清, 李振朝, 等. 青藏高原深层土壤热扩散率的时空分布特征 [J]. 土壤学报, 2018, 55(2): 351-359.

[60] 李火青, 吴新萍, 买买提艾力·买买提依明, 等. 塔克拉玛干沙漠地表浅层土壤热扩散率、温度和热通量计算方法的比较研究[J]. 土壤通报 2016, 47(4): 805-813.

[61] Mcneill J D. Use of Electromagnetic Methods for Groundwater Studies [J]. Geotechnical Environmental geophysics, 1990, 191-218.

[62] 曾召田, 范理云, 莫红艳, 等. 土壤热导率的影响因素实验研究 [J]. 太阳能学报, 2018, 39(2): 377-384.

[63] 于明志, 彭晓峰, 方肇洪. 沙土孔隙内水分形态及分布 [J]. 山东建筑大学学报, 2007, 22(6): 526-530.

[64] Clavier C, Coates G, Dumanoir J. Theoretical and Experimental Bases for the Dual-Water Model for Interpretation of Shaly Sands [J]. Socpetrengj, 1984, 24(2): 153-168.

[65] Melchers R E, Wells T. Correlation between soil electrical resistivity, polarisation resistance and corrosion of steel [J]. Corrosion Engineering, Science and Technology, 2018, 53(7): 524-530.

[66] 陈四利, 宁宝宽, 鲍文博, 等. 水泥土细观破裂过程的损伤本构模型 [J]. 岩土力学, 2007, 28(1): 93-96.

[67] 杨孟林, 王琮玉, 胡凌云, 等. NaCl和H2SO4溶液导热率的测定 [J]. 西北大学学报：自然科学版, 2000, 30(2): 124-126.

[68] Chao L, Sun Q, Zhang W. Effects of NaCl concentration on thermal conductivity of clay with cooling [J]. Bulletin of Engineering Geology and The Environment, 2020,79(3):1449-1459.

[69] Palomino A M, Santamarina J C. Fabric map for kaolinite: Effects of pH and ionic concentration on behavior [J]. Clays and Clay Minerals, 2005, 53(3): 211-223.

[70] 牛军, 孔繁杰. 土微观结构下的冻土热参数研究 [J]. 天津建设科技, 2019, 29(4): 3-7.