Seepage characteristics of preferential flow in loess
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摘要: 水对黄土灾害起控制作用,在自然边坡、工程边坡中,水的过量入渗均会对其稳定性造成影响,而优势通道在黄土水入渗中起到重要作用。通过物探手段探测研究区裂隙发育特征,通过自主设计单环渗透仪测量水在隐伏裂隙区的入渗量并结合高密度电法实时监测入渗过程,最后通过数值模拟分析优势流和基质流共同作用下不同灌溉强度下水的入渗特征。主要得出以下结论：①黄土中易被忽视的隐伏裂隙可为渗流提供优势通道。②揭示了高强度灌溉条件下黄土中优势通道中水的渗流过程：水优先入渗至优势通道内,同时在顶部渗流边界进行基质流入渗,水也会沿着优势通道向四周进行基质流扩散,该类基质流扩散以非饱和入渗的形式进行。③数值模拟中基质流和优势流耦合作用下不同灌溉强度下的渗流特征：高灌溉强度短历时条件下,优势流起主导作用,灌溉水可快速入渗至底部导致地下水位抬升,顶部基质流渗流为非饱和入渗；低灌溉强度长历时条件下,基质流起主导作用,基质流以饱和状态入渗,在地表形成一层饱和层,而优势流以非饱和状态入渗。Abstract: The water infiltration in loess slopes is of great significance for the change of physical and mechanical properties of soil. There are many preferential channels in loess and the study on the preferential flow is crucial for the understanding of water infiltration process in loess. The distribution of fractures especially the microscale fractures is detected by using the electrical resistivity tomography (ERT) and geological radar. Furthermore an in-situ single-ring infiltrometer test is carried out in the hidden fracture areas to monitor the infiltration process. Based on the in-situ test results, a single-permeability model and a dual-permeability model are set up to simulate the infiltration process in the preferential channel. The conclusions can be drawn as follows: (1) The hidden fractures in loess are significant for the preferential flow which is always ignored in the engineering. (2) The in-situ infiltration process in preferential flow channels is revealed: the water infiltrates into the fractures first, then the unsaturated infiltration process begins, and water infiltrates downwards uniformly, at the same time the water in the preferential flow channels spreads into the matrix flow area. (3) The numerical method simulates two types of irrigation conditions: high intensity with a short duration and low intensity with a long duration. For the high intensity case, the preferential flow dominates and it has a positive effect on the infiltration, and the irrigation water infiltrates quickly into the deep soil and induces the increase of groundwater with the top matrix domain unsaturated. For the low intensity case, the matrix flow dominates and it has a saturated infiltration state.
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图 7 竖向剖面电阻率变化率分布图
Figure 7. Change rate of electronic resistivity for different sections
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图 10 不同模型饱和度和水转换率变化图
Figure 10. Saturations and water exchange rates by different models
表 1 各研究方法统计表
Table 1 Summary of various methods
探测对象 方法 参数 测量长度/m 测量深度/m 分辨率/m 水位 ERT 电极距3 m 207.0 35 1.50 裂隙 ERT 电极距0.5 m 34.5 6 0.25 隐伏 GPR 频率400 MHz 4.0 2 0.01 裂隙 入渗 ERT 电极距0.2 m 14.0 2 0.10 过程 入渗 单 常水头10 cm 采样频率1 min 水量 环 注： ERT为高密度电法；GPR为探地雷达。
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表 2 数值模拟参数统计表
Table 2 Summary of parameters
符号 名称 数值 θs 饱和含水率 0.4 θr 残余含水率 0.04 Ks 饱和渗透系数/(cm·h-1) 2.56 Ksf 优势流的Ks/(cm·h-1) 23.49 Ksm 基质流的Ks/(cm·h-1) 0.2349 αw 水量转换系数/m-2 0.2 αBC Brooks-Corey拟合参数/cm-1 0.068 nBC Brooks-Corey拟合参数 0.322 lBC Brooks-Corey拟合参数 1
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[1] 周葆春, 陈志. 压实膨胀土非饱和渗水系数函数的密度与水力滞回效应[J]. 岩土工程学报, 2019, 41(10): 1800-1808. https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC201910004.htm ZHOU Bao-chun, CHEN Zhi. Effects of density and hysteresis on hydraulic conductivity function of compacted expansive soil[J]. Chinese Journal of Geotechnical Engineering, 2019, 41(10): 1800-1808. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC201910004.htm
[2] 胡海军. 增湿情况重塑黄土非饱和渗透系数的测定方法研究[J]. 水利学报, 2018, 49(10): 1216-1226. https://www.cnki.com.cn/Article/CJFDTOTAL-SLXB201810005.htm HU Hai-jun. Study on the method for determining the unsaturated permeability coefficient of loess in humidificatio[J]. Journal of Hydraulic Engineering, 2018, 49(10): 1216-1226. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-SLXB201810005.htm
[3] 洪勃, 李喜安, 陈广东, 等. 重塑马兰黄土渗透性试验研究[J]. 工程地质学报, 2016, 24(2): 276-283. https://www.cnki.com.cn/Article/CJFDTOTAL-GCDZ201602017.htm HONG Bo, LI Xi-an, CHEN Guang-dong, et al. Experimental study of permeability of remolded Malan loess[J]. Journal of Engineering Geology, 2016, 24(2): 276-283. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-GCDZ201602017.htm
[4] 王铁行, 杨涛, 鲁洁. 干密度及冻融循环对黄土渗透性的各向异性影响[J]. 岩土力学, 2016, 37(增刊1): 72-78. https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX2016S1009.htm WANG Tie-hang, YANG Tao, LU Jie. Influence of dry density and freezing-thawing cycles on anisotropic permeability of loess[J]. Rock and Soil Mechanics, 2016, 37(S1): 72-78. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX2016S1009.htm
[5] 赵宽耀, 许强, 张先林, 等. 黑方台浅层黄土渗透特性对比试验研究[J]. 工程地质学报, 2018, 26(2): 459-466. https://www.cnki.com.cn/Article/CJFDTOTAL-GCDZ201802023.htm ZHAO Kuan-yao, XU Qiang, ZHANG Xian-lin, et al. The research on the infiltration characteristics in the topsoil of Heifangtai in Gansu Province[J]. Engineering Geology. 2018, 26(2): 459-466. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-GCDZ201802023.htm
[6] 梁燕, 邢鲜丽, 李同录, 等. 晚更新世黄土渗透性的各向异性及其机制研究[J]. 岩土力学, 2012, 33(5): 1313-1318. https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX201205005.htm LIANG Yan, XING Xian-li, LI Tong-lu, et al. Study of the anisotropic permeability and mechanism of Q3 loess[J]. Rock and Soil Mechanics, 2012, 33(5): 1313-1318. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX201205005.htm
[7] 张晓周, 卢婷, 卢玉东, 等. 扫描电镜下泾阳南塬马兰黄土的孔隙特征[J]. 水土保持通报, 2018, 38(3): 212-216. https://www.cnki.com.cn/Article/CJFDTOTAL-STTB201803034.htm ZHANG Xiao-zhou, LU Ting, LU Yu-dong, et al. Characteristics of malan loess porosity in south Jingyang plateau under scanning electron microscope[J]. Soil and water Conservation bulletin, 2018, 38(3): 212-216. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-STTB201803034.htm
[8] 延恺, 谷天峰, 王家鼎, 等. 基于显微CT图像的黄土微结构研究[J]. 水文地质工程地质, 2018, 55(5): 1098-1107. https://www.cnki.com.cn/Article/CJFDTOTAL-SWDG201803009.htm YAN Kai, GU Tian-feng, WANG Jia-ding, et al. A study of the micro-configuration of loess based on micro-CT images[J]. Journal of Soil Science, 2018, 55(5): 1098-1107. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-SWDG201803009.htm
[9] 徐世民, 吴志坚, 赵文琛, 等. 基于Matlab和IPP的黄土孔隙微观结构研究[J]. 地震工程学报, 2017, 39(1): 80-87. https://www.cnki.com.cn/Article/CJFDTOTAL-ZBDZ201701012.htm XU Shi-ming, WU Zhi-jian, ZHAO wen-chen, et al. Study on microstructure of loess porosity based on Matlab and IPP[J]. Journal of Earthquake Engineering, 2017, 39(1): 80-87. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-ZBDZ201701012.htm
[10] 胡再强, 沈珠江. 非饱和黄土的结构性研究[J]. 岩石力学与工程学报, 2000, 19(6): 775-775. https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX200006018.htm HU Zai-qiang, SHEN Zhu-jiang. Structural study of unsaturated loess[J]. Chinese Journal of Rock Mechanics and Engineering, 2000, 19(6): 775-775. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX200006018.htm
[11] 张泽, 周泓, 秦琦, 等. 冻融循环作用下黄土的孔隙特征试验[J]. 吉林大学学报(地球科学版), 2017, 47(3): 839-847. https://www.cnki.com.cn/Article/CJFDTOTAL-CCDZ201703017.htm ZHANG Ze, ZHOU Hong, QIN Qi, et al. Experimental study on porosity characteristics of loess under freezing-thawing cycle[J]. Journal of Jilin University (Earth Science Edition), 2017, 47(3): 839-847. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-CCDZ201703017.htm
[12] 鞠忻倪. 黄土沟壑区不同地形部位土壤大孔隙特征研究[J]. 土壤学报, 2018, 55(5): 1098-1107. https://www.cnki.com.cn/Article/CJFDTOTAL-TRXB201805006.htm JU Xin-ni. Characteristics of soil macropore in different topographical parts of the loess plateau[J]. Journal of Soil Science, 2018, 55(5): 1098-1107. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-TRXB201805006.htm
[13] 张耀, 胡再强, 陈昊, 等. 酸性溶液对黄土结构改良的试验研究[J]. 岩土工程学报, 2018, 40(4): 681-688. https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC201804018.htm ZHANG Yao, HU Zai-qiang, CHEN Hao, et al. Experimental study on evolution of loess structure using acid solutions[J]. Chinese Journal of Geotechnical Engineering, 2018, 40(4): 681-688. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC201804018.htm
[14] 李佳, 高广运, 黄雪峰, 等. 非饱和原状黄土边坡浸水试验研究[J]. 岩土力学与工程学报, 2011, 30(5): 1043-1048. https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX201105023.htm LI Jia, GAO Guang-yuan, HUANG Xue-feng, et al. Experimental study on water immersion in unsaturated undisturbed loess slope[J]. Chinese Journal of Rock Mechanics and Engineering, 2011, 30(5): 1043-1048. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX201105023.htm
[15] 卢靖, 程彬. 非饱和黄土土水特征曲线的研究[J]. 岩土工程学报, 2007, 29(10): 1591-1592. https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC200710030.htm LU Jing, CHENG Bin. Research on soil-water characteristic curve of unsaturated loess[J]. Chinese Journal of Geotechnical Engineering, 2007, 29(10): 1591-1592. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC200710030.htm
[16] 王铁行, 李宁, 谢定义. 非饱和黄土重力势、基质势和温度势探讨[J]. 岩土工程学报, 2004, 26(5): 715-718. https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC200405029.htm WANG Tie-hang, LI Ning, XIE Ding-yi. GravitationaI potential, matrlx suction and thermal potentiaI of unsaturated loess soil[J]. Chinese Journal of Geotechnical Engineering, 2004, 26(5): 715-718. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC200405029.htm
[17] 谌文武. 基于不同渗透持时的非饱和黄土渗透系数预测分析[J]. 岩土工程学报, 2018, 40(增刊1): 22-27. https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC2018S1005.htm ZHAN Wen-wu. Prediction of coefficient of permeability of unsaturated loess with different seepage durations[J]. Chinese Journal of Geotechnical Engineering, 2018, 40(S1): 22-27. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC2018S1005.htm
[18] 李萍, 李同录, 王阿丹, 等. 黄土中水分迁移规律现场试验研究[J]. 岩土力学, 2013, 34(5): 1331-1339. https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX201305016.htm LI Ping, LI Tong-lu, WANG A-dan, et al. Field experimental study on the law of water migration in loess[J]. Rock and Soil Mechanics, 2013, 34(5): 1331-1339. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX201305016.htm
[19] 李萍, 李同录, 王红, 等. 非饱和黄土土–水特征曲线与渗透系数Childs &Collis-Geroge模型预测[J]. 岩土力学, 2013, 34(增刊2): 184-189. LI Ping, LI Tong-lu, WANG Hong, et al. Prediction of soil-water characteristic curve and permeability coefficient of unsaturated loess with Childs & Collis-Geroge model[J]. Rock and Soil Mechanics, 2013, 34(S2): 184-189. (in Chinese)
[20] 穆青翼, 党影杰, 董琪, 等. 原状和压实黄土持水特性及湿陷性对比试验研究[J]. 岩土工程学报, 2019, 41(8): 1496-1504. https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC201908017.htm MU Qing-yi, DANG Ying-jie, DONG Qi, et al. Water-retention characteristics and collapsibity behaviors: comparison between intact and compacted loesses[J]. Chinese Journal of Geotechnical Engineering, 2019,41(8): 1496-1504. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC201908017.htm
[21] 许领, 李宏杰, 吴多贤. 黄土台缘滑坡地表水入渗问题分析[J]. 中国地质灾害与防治学报, 2008, 19(2): 32-35. https://www.cnki.com.cn/Article/CJFDTOTAL-ZGDH200802006.htm XU Ling, LI Hong-jie, WU Duo-xian. Discussion on infiltration of surface water and their significance to terrace loess landslides[J]. The Chinese Journal of Geological Hazard and Control, 2008, 19(2): 32-35. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-ZGDH200802006.htm
[22] 杨博, 张虎元, 赵天宇, 等. 改性黄土渗透性与孔隙结构的依存关系[J]. 水文地质工程地质, 2011, 38(6): 96-101. https://www.cnki.com.cn/Article/CJFDTOTAL-SWDG201106018.htm YNAG Bo, ZHANG Hu-yuan, ZHAO Tina-yu, et al. Responsibility of permeability of modified loess soil on microstructure[J]. Hydrogeology & Engineering Geology, 2011, 38(6): 96-101. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-SWDG201106018.htm
[23] 亓星, 许强, 李斌, 等. 甘肃黑方台黄土滑坡地表水入渗机制初步研究[J]. 工程地质学报, 2016, 24(3): 418-424. https://www.cnki.com.cn/Article/CJFDTOTAL-GCDZ201603012.htm QI Xing, XU Qiang, LI Bin, et al. Preliminary study on mechanism of surface water infiltration at Heifangtai loess landslides in Gansu[J]. Journal of Engineering Geology, 2016, 24(3): 418-424. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-GCDZ201603012.htm
[24] 张建丰, 林性粹, 王文焰. 黄土的大孔隙特征和大孔隙流研究[J]. 水土保持学报, 2003, 17(4): 168-171. https://www.cnki.com.cn/Article/CJFDTOTAL-TRQS200304046.htm ZHANG Jian-feng, LIN Xing-cui, WANG Wen-yan. Study on the large pore characteristics and large pore flow of loess[J]. Journal of Soil and Water Conservation, 2003, 17(4): 168-171. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-TRQS200304046.htm
[25] 王铁行. 非饱和黄土路基水分场的数值分析[J]. 岩土工程学报, 2008, 30(1): 41-45. https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC200801008.htm WANG Tie-hang, Moisture migration in unsaturated loess subgrade[J]. Chinese Journal of Geotechnical Engineering, 2008, 30(1): 41-45. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC200801008.htm
[26] 梁越. 孔隙流动数值模拟建模方法及孔隙流速分布规律[J]. 岩土工程学报, 2011, 33(7): 1104-1109. https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC201107018.htm LIANG Yue. Numerical simulation model for pore flows and distribution of their velocity[J]. Chinese Journal of Geotechnical Engineering, 2011, 33(7): 1104-1109. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC201107018.htm
[27] 张爱军, 康顺祥, 李鹏. 黄土滑坡体立体排水系统的三向渗流数值模拟[J]. 水土保持通报, 2004, 24(6): 6-9. https://www.cnki.com.cn/Article/CJFDTOTAL-STTB200406002.htm ZHANG Ai-jun, KANG Shun-xiang, LI Peng. 3D seepage numerical analysis of three-dimensional drainage system in loess landsliding body[J]. Soil and Water Conservation Bulletin, 2004, 24(6): 6-9. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-STTB200406002.htm
[28] 孙萍萍, 张茂省, 董英, 等. 甘肃永靖黑方台灌区潜水渗流场与斜坡稳定性耦合分析[J]. 地质通报, 2013, 32(6): 887-892. https://www.cnki.com.cn/Article/CJFDTOTAL-ZQYD201306010.htm SUN Ping-ping, ZHANG Mao-sheng, DONG Yin, et al. The coupled analysis of phreafic water flow and slope stability at Heifangtal terrace, Gansu Province[J]. Geological Bulletin of China, 2013, 32(6): 887-892. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-ZQYD201306010.htm
[29] 梁越, 陈鹏飞, 林加定, 等. 基于透明土技术的多孔介质孔隙流动特性研究[J]. 岩土工程学报, 2019, 41(7): 1361-1366. https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC201907025.htm LIANG Yue, CHEN Peng-fei, LIN Jia-ding, et al. Pore flow characteristics of porous media based on transparent soil technology[J]. Chinese Journal of Geotechnical Engineering, 2019, 41(7): 1361-1366. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC201907025.htm
[30] SHAO W, BOGAARD T A, BAKKER M, et al. Quantification of the influence of preferential flow on slope stability using a numerical modelling approach[J]. Hydrol Earth Syst Sci 2015, 19: 2197-2212. doi: 10.5194/hess-19-2197-2015.
[31] VOGEL T, GERKE H H, ZHANG R, et al. Modeling flow and transport in a two-dimensional dual-permeability system with spatially variable hydraulic properties[J]. J Hydrol, 2000, 238: 78-89.
[32] 赵宽耀, 许强. 一种适用于双环入渗的改进装置: ZL201820627927.1[P]. 2018-12-04. [33] 水利水电工程注水试验规程：SL345—2007[S]. 2007. Water Injection and Hydropower Engineering Water Injection Test Regulations: SL345—2007[S]. 2007. (in Chinese)
[34] GERKE H H, VAN GENUCHTEN M. A dual porosity model for simulating the preferential movement of water and solutes in structured porous media[J]. Water Resour Res, 1993, 29: 305-319.
[35] RAY C, ELLSWORTH T R, VALOCCHI A J, et al. An improved dual porosity model for chemical transport in macrop- orous soils[J]. J Hydrol, 1997, 193: 270-292.
[36] ARORA B, MOHANTY B P, MCGUIRE J T. Inverse estimation of parameters for multidomain flow models in soil columns with different macropore densities[J]. Water Resour Res, 2011, 47, W04512, doi: 10.1029/2010WR009451.
[37] LAINE-KAULIO H, BACKNÄS S, KARVONEN T, et al. Lateral subsurface stormflow and solute transport in a forested hillslope: a combined measurement and modeling approach[J]. Water Resour Res, 2014, 50: 8159-8178.
[38] BROOKS R, COREY A. Hydraulic Properties of Porous Media[D]. Colorado: Colorado State University, 1964.
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