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THE PERMEABILITY CHARACTERISTICS OF LOESS AND RED CLAY INTERFACE IN HEIFANGTAI AREA
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摘要: 黄土与红黏土这一地层结构组合在黑方台地区普遍存在，黄土与红黏土之间存在渗透差，在持续灌溉条件下红黏土层会出现滞水效应，从而发生层带软化现象，最终诱发滑坡。本文分别开展室内土工试验、核磁共振试验(NMR)以及颗分试验，进而研究增湿条件下黄土-红黏土界面处非饱和入渗情况以及充水孔隙变化规律。得出以下结论：(1)在入渗过程中充水孔隙体积分布曲线中峰值不断向右迁移，充水孔隙半径不断增大且分布范围逐渐变广。黄土-红黏土组合样与纯黄土相比，充水孔隙体积分布曲线中最大峰值向右迁移较慢且分布范围较窄，入渗结束后红黏土层富含水分。(2)在相同流量条件下，黄土-红黏土组合样初始含水率越高，充水孔隙体积分布曲线中最大峰值向右迁移得越慢，所对应的充水孔隙半径变化越小且在界面处滞水效应越不明显。在相同初始含水率条件下，流量越大，充水孔隙体积分布曲线中峰值向右迁移得越快，水分进入中大孔隙越多且在界面处滞水现象越明显。(3)黄土-红黏土组合样在增湿过程中发生颗粒运移，导致颗粒间接触方式发生改变，最终试样底部细颗粒含量较多，界面处粗颗粒含量较多。Abstract: The stratum structure combination of loess and red clay is common in Heifangtai area. Loess and red clay have penetration differences. Under continuous irrigation conditions,the red clay layer will have a water stagnation effect,which can cause layer softening and eventually induce landslides. In this paper,indoor geotechnical tests,NMR and particle fractionation tests were carried out respectively to study the unsaturated infiltration situation and pore change law at the interface between loess and red clay. The analysis of the test results show the following findings. (1)During the infiltration process,the peak value of the water-filled pore volume distribution map keeps moving to the right. The radius of the water-filled pore increases and the distribution range gradually becomes wider. Compared with pure loess,the maximum peak value in the water-filled pore volume distribution curve of the loess-red clay composite sample migrates more slowly to the right and has a narrower distribution range. The red clay layer is rich in water after the end of infiltration. (2)Under the same flow conditions,the higher the initial water content of the loess-red clay composite sample,the slower the peak value in the water-filled pore volume distribution curve shifts to the right,the smaller the change of the corresponding water-filled pore radius,and the water entering the medium and large. The fewer the pores,the less obvious the water stagnation effect at the interface. Under the condition of the same initial water content,the larger the flow rate,the faster the peak value in the water-filled pore volume distribution curve shifts to the right,and the corresponding water-filled pore radius is larger. The more water enters the medium and large pores,and the more obvious the phenomenon of water stagnation at the interface. (3)Particle migration occurs during the humidification process of the loess and red clay composite samples,which leads to changes in the contact mode between particles and the pore structure. The final sample contains more fine particles at the bottom and more coarse particles at the interface.
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Key words:
- NMR /
- Permeability /
- Particle migration /
- Reshape soil
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图 1 黑方台地区地层组合图
a. 黑方台某滑坡坡脚处; b. 黑方台区域典型地质剖面图
Figure 1. Stratigraphic assemblage map of Heifangtai area
图 4 不同初始含水率纯黄土充水孔隙分布图
a. 15%纯黄土充水孔隙体积分布；b. 15%纯黄土不同充水孔隙体积分布柱状图; c. 17%纯黄土充水孔隙体积分布; d. 17%纯黄土不同充水孔隙体积分布柱状图
Figure 4. The infiltration pore distribution map of pure loess with different initial water content
图 5 不同初始含水率黄土-红黏土组合样充水孔隙分布图
a. 15%黄土-红黏土组合样充水孔隙体积分布; b. 15%黄土-红黏土组合样不同充水孔隙体积分布柱状图; c. 17%黄土-红黏土组合样充水孔隙体积分布; d. 17%黄土-红黏土组合样不同充水孔隙体积分布柱状图
Figure 5. The infiltration pore distribution map of loess and red clay combined sample with different initial water content
图 6 流量0.74 mL·min-1初始含水率15%试样充水孔隙分布图
a. 0.74 mL·min-1纯黄土充水孔隙体积分布; b. 0.74 mL·min-1纯黄土充水不同充水孔隙体积分布柱状图; c. 0.74 mL·min-1黄土-红黏土组合样充水孔隙体积分布; d. 0.74 mL·min-1黄土-红黏土组合样不同充水孔隙体积分布柱状图
Figure 6. The infiltration pore distribution map of flow 0.74 mL·min-1 initial water content 15% sample
图 7 纯黄土入渗核磁共振成像图
a. 流量0.45 mL·min-1—初始含水率15%入渗图; b. 流量0.45 mL·min-1—初始含水率17%入渗图; c. 流量0.74 mL·min-1—初始含水率15%入渗图; d. 纯黄土T2谱总面积图
Figure 7. The infiltration MRI image of pure loess
图 8 黄土与红黏土组合样入渗核磁共振成像图
a. 流量0.45 mL·min-1—初始含水率15%入渗图; b. 流量0.45 mL·min-1—初始含水率17%入渗图; c. 流量0.74 mL·min-1—初始含水率15%入渗图; d. 黄土与红黏土组合样T2谱总面积图
Figure 8. The infiltration MRI image of loess and red clay combined samples
图 9 黄土与红黏土组合样颗粒运移情况图
a. 黄土与红黏土组合样底部颗分图；b. 黄土与红黏土组合样界面处颗分图
Figure 9. The diagram of particle migration of loess and red clay combined samples
表 1 入渗试验工况表
Table 1. Infiltration test condition table
序号 初始含水率/% 流量/mL·min-1 土样高度/cm N1 15 0.45 6(黄土) N2 4(黄土)+2(红黏土) N3 17 0.45 6(黄土) N4 4(黄土)+2(红黏土) N5 15 0.74 6(黄土) N6 4(黄土)+2(红黏土) 
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表 2 流量0.45 mL·min-1初始含水率15%纯黄土充水孔隙分布表
Table 2. The infiltration pore distribution table of flow 0.45 mL·min-1 initial water content 15% pure loess
时间T/min 第1个峰值对应的孔径R/μm 积分面积所占比例/% 第2个峰值对应的孔径R/μm 积分面积所占比例/% 第3个峰值对应的孔径R/μm 积分面积所占比例/% 0 0.105 99.4 9.117 0.6 — — 15 0.121 95.3 2.597 3.9 48.668 0.8 30 0.159 96.2 2.597 3.0 48.688 0.8 45 0.242 96.8 3.433 2.5 55.956 0.7 60 0.423 97.8 3.947 2.2 — — 75 0.643 97.5 6 0.9 18.323 1.6 表中“—”代表无数据
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表 3 流量0.45 mL·min-1初始含水率17%纯黄土充水孔隙分布表
Table 3. The infiltration pore distribution table of flow 0.45 mL·min-1 initial water content 17% pure loess
时间T/min 第1个峰值对应的孔径R/μm 积分面积所占比例/% 第2个峰值对应的孔径R/μm 积分面积所占比例/% 第3个峰值对应的孔径R/μm 积分面积所占比例/% 0 0.069 99.6 4.539 0.4 — — 15 0.079 95.8 1.709 3.4 42.329 0.9 30 0.105 97.5 1.709 1.7 36.815 0.9 45 0.278 97.8 3.947 2.2 — — 60 0.423 97.0 6 3.0 — — 75 0.486 94.6 6 2.0 15.936 3.4 表中“—”代表无数据
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表 4 流量0.45 mL·min-1初始含水率15%黄土-红黏土组合样充水孔隙分布表
Table 4. The infiltration pore distribution table of flow rate 0.45 mL·min-1 initial water content 15% loess and red clay combined sample
时间T/min 第1个峰值对应的孔径R/μm 积分面积所占比例/% 第2个峰值对应的孔径R/μm 积分面积所占比例/% 第3个峰值对应的孔径R/μm 积分面积所占比例/% 0 0.091 98.8 6 0.9 18.323 0.3 15 0.105 93.0 2.259 4.3 27.849 2.6 30 0.121 95.6 2.259 2.0 27.849 2.5 45 0.278 95.2 3.947 1.9 21.067 2.9 60 0.559 96.1 5.218 0.7 24.222 3.2 75 0.739 95.3 6 0.4 24.222 4.3
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表 5 流量0.45 mL·min-1初始含水率17%黄土-红黏土组合样充水孔隙分布表
Table 5. The infiltration pore distribution table of flow rate 0.45 mL·min-1 initial water content 17% loess and red clay combined sample
时间T/min 第1个峰值对应的孔径R/μm 积分面积所占比例/% 第2个峰值对应的孔径R/μm 积分面积所占比例/% 第3个峰值对应的孔径R/μm 积分面积所占比例/% 0 0.079 98.8 4.539 0.9 18.323 0.3 15 0.079 95.8 2.259 2.9 36.815 1.3 30 0.139 95.4 2.597 3.5 42.329 1.1 45 0.242 96.7 3.433 2.7 64.336 0.6 60 0.32 97.7 3.947 1.7 73.971 0.6 75 0.423 96.0 18.323 2.8 84.971 1.2
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表 6 流量0.74 mL·min-1初始含水率15%纯黄土充水孔隙分布表
Table 6. The infiltration pore distribution table of flow 0.74 mL·min-1 initial water content 15% pure loess
时间T/min 第1个峰值对应的孔径R/μm 积分面积所占比例/% 第2个峰值对应的孔径R/μm 积分面积所占比例/% 第3个峰值对应的孔径R/μm 积分面积所占比例/% 0 0.105 95.1 6.900 1.2 13.86 3.7 15 0.211 83.8 3.433 16.2 — — 30 0.487 91.7 6.898 1.4 24.22 6.9 45 1.292 95.2 36.815 4.8 — — 60 2.597 96.3 36.815 3.7 — — 表中“—”代表无数据
下载: 导出CSV
表 7 流量0.74 mL·min-1初始含水率15%黄土-红黏土组合样充水孔隙分布表
Table 7. The infiltration pore distribution table of flow rate 0.74 mL·min-1 initial water content 15% loess and red clay combined sample
时间T/min 第1个峰值对应的孔径R/μm 积分面积所占比例/% 第2个峰值对应的孔径R/μm 积分面积所占比例/% 第3个峰值对应的孔径R/μm 积分面积所占比例/% 0 0.105 0.992 24.220 0.8 — — 15 0.159 93.500 3.433 4.5 48.668 2.0 30 0.320 95.900 4.539 2.0 18.323 2.1 45 0.851 0.972 27.849 2.8 — — 60 1.486 91.900 32.020 8.1 — — 表中“—”代表无数据
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Bai Y,Chen Y Q,Zhang X H,et al. 2021. Study on changes of fine microstructure and macro-mechanical properties of landslide paleosoil under freeze-thaw cycle[J]. Yangtze River,52 (7): 192-197, 203. Cao C W. 2018. Study on unsaturated infiltration characteristics of losee in Hei Fangtai, Gansu Province[D]. Chengdu: Chengdu University of Technology. Deng K J. 2010. Theory and application of nuclear magnetic resonance logging[M]. Dongying: China University of Petroleum Press. Fan C Y. 2013. Microstructure of loess in Heifangtai and its indication of the landslide cause[D]. Lanzhou: Lanzhou University. He P, Xu Q, Liu J L, et al. 2020. Effect of pore size distribution on percolation characteristics of loess based on nuclear magnetic resonance technique[J]. Science Technology and Engineering, 20 (30): 12355-12360. doi: 10.3969/j.issn.1671-1815.2020.30.014 Jia H L, Ding S, Wang T, et al. 2019. A NMR based experimental simulation of snowmelt infiltrating into bedrock[J]. Journal of Glaciology and Geocryology, 41 (5): 1130-1137. Jiang Q Q, Liu L L, Jiao Y Y, et al. 2019. Strength properties and microstructure characteristics of slip zone soil subjected to wetting-drying cycles[J]. Rock and Soil Mechanics, 40 (3): 1005-1012, 1022. Jiao H. 2019. Experimental study on strength deterioration and microscopic mechanism of loess under free-thaw and salt interaction[D]. Xi'an: Xi'an University of Science and Technology. Ju Y H, Jiang M H, Liu L, et al. 2022. Comparative experimental study on particle fractions measurement by laser particle sizer method and traditional standard method[J]. Geotechnical Investigation & Surveying, 50 (8): 1-6. Li J L, Zhou K P, Zhang Y M, et al. 2012. Experimental study of rock porous structure damage characteristics under condition of freezing-thawing cycles based on unclear magnetic resonance technique[J]. Chinese Journal of Rock Mechanics and Engineering, 31 (6): 1208-1214. doi: 10.3969/j.issn.1000-6915.2012.06.016 Li T G, Kong L W, Wang J T, et al. 2021. Trimodal pore structure evolution characteristics and mechanical effects of expansive soil in seasonally frozen areas based on NMR test[J]. Rock and Soil Mechanics, 42 (10): 2741-2754. Li Z M, Zeng W X, Gao M L, et al. 2014. Nuclear magnetic resonance experimental study on the characteristics of pore-size distribution in muck under several typical loading cases[J]. Acta Physica Sinica, 63 (5): 376-382. Liao H J, Liu S H, He Y Q, et al. 2022. Study on fractal dimension of pore size and water retention characteristics of loess [J]. Journal of Northwest University (Natural Science Eidtion), 52(3): 416-422. Lin Y Z, Jian W B, Dou H Q, et al. 2022. Rainfall infiltration mechanisms of soil columns under conductivity[J]. Journal of Engineering Geology, 30 (2): 394-406. Liu M D, Guo Y, Shan W, et al. 2021. Effects of particle gradation and compaction degree on soil-water characteristic curve of subgrade[J]. Water Power, 47 (4): 39-42, 62. doi: 10.3969/j.issn.0559-9342.2021.04.009 Liu Y J, Li Z M, Guo L F, et al. 2018. Pore characteristics of soft soil under triaxial shearing measured with NMR[J]. Chinese Journal of Rock Mechanics and Engineering, 37 (8): 1924-1932. Matteson A, Tomanic J P, Herron M. 2000. NMR relaxation of clay-brine mixtures[J]. SPE Reservoir Evaluation & Engineering, 3 (5): 408-413. Ren X H, Xu Q, Zhao K Y, et al. 2020. Effect of repeated infiltration on permeability characteristics of remolded loess[J]. Bulletin of Geological Science and Technology, 39 (2): 130-138. Shi L J, Qiao X Y, Zeng L, et al. 2018. Loess moisture migration in Heifangtai of Gansu Province[J]. Arid Zone Research, 35 (4): 813-820. Song N X, Chen B X, Wang C L, et al. 2017. Estimation of core fracture porosity by T2-NMR spectroscopy[J]. Petrochemical Industry Technology, 24(2): 127. doi: 10.3969/j.issn.1006-0235.2017.02.094 Sun P P. 2020. Water sensitivity of loess and prediction of rainfall induced shallow loess landslides[D]. Xi'an: Northwest University. Wang X, Yang B, Gu T F, et al. 2018. Study of loess compression test in Heifangtai, Gansu[J]. Journal of Shaanxi University of Technology(Natural Science Edition), 34 (2): 16-20, 44. Yang Y. 2019. Experimental investigation on water permeability of unsaturated soils under hydro-mechanical coupled conditions[D]. Beijing: Beijing Jiaotong University. Ye W J, Qiang Y H, Jing H J, et al. 2022. Freeze-thaw cycle experiment of loess paleosol with different water content based on nuclear magnetic resonance[J]. Journal of Engineering Geology, 30 (1): 144-153. Ye W J, Wu Y T, Yang G S, et al. 2019. Study on microstructure and macro-mechanical properties of paleosol under dry-wet cycles[J]. Chinese Journal of Rock Mechanics and Engineering, 38 (10): 2126-2137. Yi L. 2017. Tension crack of loess tableland edge extension mechanism and effect of landslide research[D]. Xi'an: Chang'an University. Zhang W Q. 2019. Research on High-precision deformation monitoring and prediction methods[D]. Xi'an: Chang'an University. Zhao K Y, Xu Q, Zhang X L, et al. 2018. Infiltration characteristics of topsoil at Heifangtai in Gansu province[J]. Journal of Engineering Geology, 26 (2): 459-466. Zhao K Y. 2021. Study on the groundwater system and its effects on landslides in Heifangtai loess terrace, northwest China[D]. Chengdu: Chengdu University of Technology. Zhu L F. 2019. Analysis of control factors and external force for the landslides in Heifangtai area[J]. Northwestern Geology, 52 (3): 217-222. Zou X Y, Xu Q, Zhao K Y, et al. 2020. Microscopic study on permeability change of loess in Heifangtai terrace under soaking[J]. Yangtze River, 51 (6): 166-171. 白杨, 陈义乾, 张小辉. 2021. 冻融循环下滑坡古土壤细微观结构及力学性能研究[J]. 人民长江, 52 (7): 192-197, 203. https://www.cnki.com.cn/Article/CJFDTOTAL-RIVE202107032.htm 曹从伍. 2018. 甘肃黑方台黄土非饱和入渗特性研究[D]. 成都: 成都理工大学. 邓克俊. 2010. 核磁共振测井理论及应用[M]. 东营: 中国石油大学出版社. 樊成意. 2013. 黑方台黄土的微观结构及对滑坡成因的指示[D]. 兰州: 兰州大学. 何攀, 许强, 刘佳良, 等. 2020. 基于核磁共振技术的黄土内部孔径分布对逾渗特性的影响[J]. 科学技术与工程, 20 (30): 12355-12360. doi: 10.3969/j.issn.1671-1815.2020.30.014 贾海梁, 丁顺, 王婷, 等. 2019. 基于核磁共振的地表积雪融化入渗试验模拟[J]. 冰川冻土, 41 (5): 1130-1137. https://www.cnki.com.cn/Article/CJFDTOTAL-BCDT201905013.htm 江强强, 刘路路, 焦玉勇, 等. 2019. 干湿循环下滑带土强度特性与微观结构试验研究[J]. 岩土力学, 40 (3): 1005-1012, 1022. https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX201903020.htm 焦航. 2019. 冻融-盐共同作用下黄土强度劣化规律及其微观机理试验研究[D]. 西安: 西安科技大学. 居奕含, 蒋敏华, 刘立, 等. 2022. 激光粒度仪法与传统规范法的颗分比对试验研究[J]. 工程勘察, 50 (8): 1-6. https://www.cnki.com.cn/Article/CJFDTOTAL-GCKC202208001.htm 李杰林, 周科平, 张亚民, 等. 2012. 基于核磁共振技术的岩石孔隙结构冻融损伤试验研究[J]. 岩石力学与工程学报, 31 (6): 1208-1214. https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX201206017.htm 李甜果, 孔令伟, 王俊涛, 等. 2021. 基于核磁共振的季冻区膨胀土三峰孔隙结构演化特征及其力学效应[J]. 岩土力学, 42 (10): 2741-2754. https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX202110014.htm 李彰明, 曾文秀, 高美连, 等. 2014. 典型荷载条件下淤泥孔径分布特征核磁共振试验研究[J]. 物理学报, 63 (5): 376-382. https://www.cnki.com.cn/Article/CJFDTOTAL-WLXB201405050.htm 廖红建, 刘少华, 何玉琪, 等. 2022. 黄土孔径和持水特性的分形维数研究[J]. 西北大学学报(自然科学版), 52(3): 416-422. https://www.cnki.com.cn/Article/CJFDTOTAL-XBDZ202203006.htm 林昀昭, 简文彬, 豆红强, 等. 2022. 基于电导性能的原状土柱降雨入渗规律研究[J]. 工程地质学报, 30 (2): 394-406. doi: 10.13544/j.cnki.jeg.2021-0744 刘梦迪, 郭颖, 单炜. 2021. 颗粒级配与压实度对路基土-水特征曲线的影响[J]. 水力发电, 47 (4): 39-42, 62. https://www.cnki.com.cn/Article/CJFDTOTAL-SLFD202104009.htm 刘勇健, 李彰明, 郭凌峰, 等. 2018. 基于核磁共振技术的软土三轴剪切微观孔隙特征研究[J]. 岩石力学与工程学报, 37 (8): 1924-1932. https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX201808014.htm 任晓虎, 许强, 赵宽耀, 等. 2020. 反复入渗对重塑黄土渗透特性的影响[J]. 地质科技通报, 39 (2): 130-138. https://www.cnki.com.cn/Article/CJFDTOTAL-DZKQ202002015.htm 石兰君, 乔晓英, 曾磊, 等. 2018. 甘肃黑方台黄土水分运移规律模拟[J]. 干旱区研究, 35 (4): 813-820. https://www.cnki.com.cn/Article/CJFDTOTAL-GHQJ201804008.htm 宋南希, 陈宝新, 王翠丽, 等. 2017. 基于核磁共振T2图谱测量岩芯裂缝孔隙度[J]. 石化技术, 24(2): 127. https://www.cnki.com.cn/Article/CJFDTOTAL-SHJS201702094.htm 孙萍萍. 2020. 黄土水敏性与降雨诱发浅层黄土滑坡预测[D]. 西安: 西北大学. 王潇, 杨博, 谷天峰, 等. 2018. 甘肃黑方台黄土压缩试验研究[J]. 陕西理工大学学报(自然科学版), 34 (2): 16-20, 44. https://www.cnki.com.cn/Article/CJFDTOTAL-SXGX201802005.htm 杨雨. 2019. 水-力耦合作用下非饱和土渗流特性演化规律的试验研究[D]. 北京: 北京交通大学. 叶万军, 强艳红, 景宏君, 等. 2022. 基于核磁共振的不同含水率黄土古土壤冻融循环试验研究[J]. 工程地质学报, 30 (1): 144-153. doi: 10.13544/j.cnki.jeg.2020-466 叶万军, 吴云涛, 杨更社, 等. 2019. 干湿循环作用下古土壤细微观结构及宏观力学性能变化规律研究[J]. 岩石力学与工程学报, 38 (10): 2126-2137. https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX201910018.htm 伊龙. 2017. 黄土塬边拉张裂缝扩展机制及对滑坡的影响效应研究[D]. 西安: 长安大学. 张伟琪. 2019. 黄土滑坡高精度变形监测及预测方法研究[D]. 西安: 长安大学. 赵宽耀, 许强, 张先林, 等. 2018. 黑方台浅层黄土渗透特性对比试验研究[J]. 工程地质学报, 26 (2): 459-466. doi: 10.13544/j.cnki.jeg.2016-502 赵宽耀. 2021. 甘肃黑方台地下水系统及其对滑坡的影响研究[D]. 成都: 成都理工大学. 朱立峰. 2019. 黑方台滑坡群控制因素与外动力条件分析[J]. 西北地质, 52 (3): 217-222. https://www.cnki.com.cn/Article/CJFDTOTAL-XBDI201903022.htm 邹锡云, 许强, 赵宽耀, 等. 2020. 浸水作用下黑方台黄土渗透特性变化微观研究[J]. 人民长江, 51 (6): 166-171. https://www.cnki.com.cn/Article/CJFDTOTAL-RIVE202006029.htm -
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