Research on pore structural change of gravel soil under seepage erosion based on CT scanning
-
摘要:
碎石土作为滑坡堆积层的主要组成物质，受动水因素影响，在渗流作用下内部渗透压力的变化导致土颗粒流失，造成细观结构和力学性质随之发生改变，从而影响滑坡整体稳定性。目前，渗流作用下不同渗透压力状态的孔隙结构变化规律研究较少。通过自主设计的渗流装置对碎石土试样开展室内渗流侵蚀试验，并利用CT扫描技术获取试样渗流侵蚀过程的内部孔隙图像数据。通过孔隙识别和参数提取，得到了不同渗流时刻试样内部孔隙率、等效直径等细观参数。构建孔隙网络模型，分析了渗流作用下连通孔隙的孔喉半径、喉道长度和配位数的变化规律。结果表明：水力梯度的逐步升高会改变碎石土内部孔隙分布，土颗粒的流失造成孔隙率增大，孔隙数量先增加后减少，孔隙体积增加；渗流作用下孔隙发生扩张和连通，孔隙之间连通性增强，平均孔喉半径和配位数均随着水力梯度的升高而增加。研究结果可以为碎石土滑坡的预防与治理提供一定的理论支撑。
Abstract:As the main component of the landslide accumulation layer, gravel soil is affected by hydrodynamic factors; the change of internal seepage pressure leads to the loss of soil particles, resulting in the change of meso structure and mechanical properties, and thus affecting the overall stability of the landslide. To analyze the evolution of the internal pore microstructure of the crushed soil during the seepage process, the indoor seepage erosion test was carried out on the crushed soil specimen by the self-designed seepage device, using CT scanning to obtain internal pore image data of the seepage erosion process of crushed stone soil samples. Through the identification of porosity and parameter extraction, the changes of mesoscopic parameters such as internal porosity and equivalent diameter of the specimen during the seepage process were analyzed. A pore network model was constructed to analyze the variation of pore radius, throat length, and coordination number of connected pores under different seepage conditions. The results show that the gradual increase of the hydraulic gradient will change the pore distribution in the internal soil. The soil particle erosion leads to the porosity increasing, the pore quantity increasing first and then decreasing, and the total pore volume increasing. Seepage will promote the pore expansion and penetration, and enhance the pore connectivity. The average pore throat radius and average coordination number increase with the hydraulic gradient increasing. This study can provide theoretical significance for the prevention and treatment of gravel soil landslides.
-
Key words:
- gravel soil /
- seepage erosion /
- CT /
- pore microstructure /
- landslide
-
-
表 1 碎石土的基本物理指标
Table 1. Basic physical properties of gravels soil
参数 干密度/（g·cm−3） 比重/（g·cm−3） 天然含水率/% 不均匀系数 曲率系数 指标值 1.83 2.72 1.40 38.38 21.82 
下载: 导出CSV
表 2 CT图像处理识别的孔隙体积及孔隙率计算结果
Table 2. Computational pore volume and porosity identified by CT image processing specimens
扫描阶段 Scan1 Scan2 Scan3 Scan4 孔隙总
体积/mm377004 82520 99662 120479 连通孔隙
体积/mm366776 72544 89489 113214 体孔隙率/% 13.8 14.8 17.3 21.4 连通率/% 86.7 87.9 89.8 94.0
下载: 导出CSV
表 3 孔隙等效直径体积分数
Table 3. Statistical volume fraction of equivalent pore diameter
/% 等效直径/mm <0.8 0.8～<1.6 1.6～2.4 >2.4 Scan1 2.76 10.79 14.88 71.57 Scan2 2.42 9.56 13.61 74.40 Scan3 2.01 9.08 13.43 75.48 Scan4 0.98 4.43 8.05 86.54
下载: 导出CSV
表 4 孔隙网络模型定量参数分析
Table 4. Quantitative parameter analysis of pore network model
扫描阶段 Scan1 Scan2 Scan3 Scan4 连通孔隙数量 10596 10320 13371 8443 孔喉数量 15505 15538 15622 15682 平均配位数 2.96 3.03 3.67 3.71 平均孔喉长度/mm 3.33 3.38 3.62 4.06 平均孔喉半径/mm 0.41 0.42 0.44 0.60
下载: 导出CSV
表 5 不同阶段下孔隙体积增加量与土颗粒流失量
Table 5. The increase in pore volume and soil particle loss at different stages
扫描
场景孔隙体积
/mm3孔隙体积变化
/mm3土颗粒
流失/g土颗粒流失
变化/gScan1 77004 0 Scan2 82520 5516 13.4 13.4 Scan3 99662 17142 44.3 30.9 Scan4 120479 20817 78.5 34.2 注：孔隙体积变化与土颗粒流失变化中，其值均为后一次扫描时得到的数值与前一次扫描时得到的数值之差。
下载: 导出CSV
-
[1] 中华人民共和国建设部. 岩土工程勘察规范:GB 50021—2001[S]. 北京:中国建筑工业出版社,2004. [Ministry of Construction of the People’s Republic of China. Code for investigation of geotechnical engineering:GB 50021—2001[S]. Beijing:China Architecture & Building Press,2004. (in Chinese)]
Ministry of Construction of the People’s Republic of China. Code for investigation of geotechnical engineering: GB 50021—2001[S]. Beijing: China Architecture & Building Press, 2004. （in Chinese） [2] 齐永正,杨子明,刘玮民,等. 水位升降与水下冲刷作用下边坡破坏试验研究[J]. 人民黄河,2022,44(2):51 − 54. [QI Yongzheng,YANG Ziming,LIU Weimin,et al. Experimental study on slope failure under the action of water level fluctuations and underwater scours[J]. Yellow River,2022,44(2):51 − 54. (in Chinese with English abstract)]
QI Yongzheng, YANG Ziming, LIU Weimin, et al . Experimental study on slope failure under the action of water level fluctuations and underwater scours[J]. Yellow River,2022 ,44 （2 ）:51 −54 . （in Chinese with English abstract）[3] 戴邵衡,张升,童晨曦,等. 循环荷载下染色标定砂土内部侵蚀试验研究[J]. 岩石力学与工程学报,2022,41(2):423 − 432. [DAI Shaoheng,ZHANG Sheng,TONG Chenxi,et al. Experimental study on internal erosion of dyed sands under cyclic loading[J]. Chinese Journal of Rock Mechanics and Engineering,2022,41(2):423 − 432. (in Chinese with English abstract)]
DAI Shaoheng, ZHANG Sheng, TONG Chenxi, et al . Experimental study on internal erosion of dyed sands under cyclic loading[J]. Chinese Journal of Rock Mechanics and Engineering,2022 ,41 （2 ）:423 −432 . （in Chinese with English abstract）[4] 沈辉,罗先启,毕金锋. 土石混合体渗透侵蚀特性数值模拟研究[J]. 岩土力学,2017,38(5):1497 − 1502. [SHEN Hui,LUO Xianqi,BI Jinfeng. Numerical simulation of internal erosion characteristics of block in matrix soil aggregate[J]. Rock and Soil Mechanics,2017,38(5):1497 − 1502. (in Chinese with English abstract)]
SHEN Hui, LUO Xianqi, BI Jinfeng . Numerical simulation of internal erosion characteristics of block in matrix soil aggregate[J]. Rock and Soil Mechanics,2017 ,38 （5 ）:1497 −1502 . （in Chinese with English abstract）[5] BIANCHI F,WITTEL F K,THIELMANN M,et al. Tomographic study of internal erosion of particle flows in porous media[J]. Transport in Porous Media,2018,122(1):169 − 184. doi: 10.1007/s11242-017-0996-8
[6] DONG Hui,HUANG Runqiu,GAO Qianfeng. Rainfall infiltration performance and its relation to mesoscopic structural properties of a gravelly soil slope[J]. Engineering Geology,2017,230:1 − 10. doi: 10.1016/j.enggeo.2017.09.005
[7] 李伟一,钱建固,尹振宇,等. 间断级配砂土渗流侵蚀现象的计算流体力学-离散元耦合模拟[J]. 岩土力学,2021,42(11):3191 − 3201. [LI Weiyi,QIAN Jiangu,YIN Zhenyu,et al. Simulation of seepage erosion in gap graded sand soil using CFD-DEM[J]. Rock and Soil Mechanics,2021,42(11):3191 − 3201. (in Chinese with English abstract)]
LI Weiyi, QIAN Jiangu, YIN Zhenyu, et al . Simulation of seepage erosion in gap graded sand soil using CFD-DEM[J]. Rock and Soil Mechanics,2021 ,42 （11 ）:3191 −3201 . （in Chinese with English abstract）[8] 冯上鑫,柴军瑞,许增光,等. 基于核磁共振技术研究渗流作用下土石混体细观结构的变化[J]. 岩土力学,2018,39(8):2886 − 2894. [FENG Shangxin,CHAI Junrui,XU Zengguang,et al. Mesostructural change of soil-rock mixtures based on NMR technology[J]. Rock and Soil Mechanics,2018,39(8):2886 − 2894. (in Chinese with English abstract)]
FENG Shangxin, CHAI Junrui, XU Zengguang, et al . Mesostructural change of soil-rock mixtures based on NMR technology[J]. Rock and Soil Mechanics,2018 ,39 （8 ）:2886 −2894 . （in Chinese with English abstract）[9] 孟生勇,江兴元,杨义,等. 降雨诱发堆积体滑坡水土响应与稳定性时空演化试验研究[J]. 水文地质工程地质,2023,50(1):104 − 112. [MENG Shengyong,JIANG Xingyuan,YANG Yi,et al. An experimental study of spatial-temporal evolution of water-soil response and stability of a rainfall-induced accumulation landslide[J]. Hydrogeology & Engineering Geology,2023,50(1):104 − 112. (in Chinese with English abstract)]
MENG Shengyong, JIANG Xingyuan, YANG Yi, et al . An experimental study of spatial-temporal evolution of water-soil response and stability of a rainfall-induced accumulation landslide[J]. Hydrogeology & Engineering Geology,2023 ,50 （1 ）:104 −112 . （in Chinese with English abstract）[10] 杨志华,吴瑞安,郭长宝,等 川西巴塘断裂带地质灾害效应与典型滑坡发育特征[J]. 中国地质,2022,49(2):355 − 368. [YANG Zhihua,WU Ruian,GUO Changbao,et al. Geo-hazard effects and typical landslide characteristics of the Batang fault zone in the western Sichuan[J]. Geology in China,2022,49(2):355 − 368. (in Chinese with English abstract)]
YANG Zhihua, WU Ruian, GUO Changbao, et al. Geo-hazard effects and typical landslide characteristics of the Batang fault zone in the western Sichuan[J]. Geology in China, 2022, 49（2）: 355 − 368. （in Chinese with English abstract） [11] 黄达,匡希彬,罗世林. 三峡库区藕塘滑坡变形特点及复活机制研究[J]. 水文地质工程地质,2019,46(5):127 − 135. [HUANG Da,KUANG Xibin,LUO Shilin. A study of the deformation characteristics and reactivation mechanism of the Outang landslide near the Three Gorges Reservoir of China[J]. Hydrogeology & Engineering Geology,2019,46(5):127 − 135. (in Chinese with English abstract)]
HUANG Da, KUANG Xibin, LUO Shilin . A study of the deformation characteristics and reactivation mechanism of the Outang landslide near the Three Gorges Reservoir of China[J]. Hydrogeology & Engineering Geology,2019 ,46 （5 ）:127 −135 . （in Chinese with English abstract）[12] 彭家奕,张家发,沈振中,等. 颗粒形状对粗粒土孔隙特征和渗透性的影响[J]. 岩土力学,2020,41(2):592 − 600. [PENG Jiayi,ZHANG Jiafa,SHEN Zhenzhong,et al. Effect of grain shape on pore characteristics and permeability of coarse-grained soil[J]. Rock and Soil Mechanics,2020,41(2):592 − 600. (in Chinese with English abstract)]
PENG Jiayi, ZHANG Jiafa, SHEN Zhenzhong, et al . Effect of grain shape on pore characteristics and permeability of coarse-grained soil[J]. Rock and Soil Mechanics,2020 ,41 （2 ）:592 −600 . （in Chinese with English abstract）[13] NI Xiaoming,MIAO Jie,LV Runsheng,et al. Quantitative 3D spatial characterization and flow simulation of coal macropores based on μCT technology[J]. Fuel,2017,200:199 − 207. doi: 10.1016/j.fuel.2017.03.068
[14] 杨瑨,侯贺晟,符伟,等. 松科二井深层沙河子组泥岩三维显微CT成像及对深部油气预测的启示[J]. 地质通报,2020,39(7):1006 − 1014. [YANG Jin,HOU Hesheng,FU Wei,et al. 3D microscopic CT imaging and significance of SK-2 deep mudstone of Shahezi Group[J]. Geological Bulletin of China,2020,39(7):1006 − 1014. (in Chinese with English abstract)]
YANG Jin, HOU Hesheng, FU Wei, et al . 3D microscopic CT imaging and significance of SK-2 deep mudstone of Shahezi Group[J]. Geological Bulletin of China,2020 ,39 （7 ）:1006 −1014 . （in Chinese with English abstract）[15] 李易霖,张云峰,丛琳,等. X-CT扫描成像技术在致密砂岩微观孔隙结构表征中的应用——以大安油田扶余油层为例[J]. 吉林大学学报(地球科学版),2016,46(2):379 − 387. [LI Yilin,ZHANG Yunfeng,CONG Lin,et al. Application of X-CT scanning technique in the characterization of micro pore structure of tight sandstone reservoir:An example from Fuyu oil layer in Daan oilfield[J]. Journal of Jilin University (Earth Science Edition),2016,46(2):379 − 387. (in Chinese with English abstract)]
LI Yilin, ZHANG Yunfeng, CONG Lin, et al . Application of X-CT scanning technique in the characterization of micro pore structure of tight sandstone reservoir: An example from Fuyu oil layer in Daan oilfield[J]. Journal of Jilin University （Earth Science Edition）,2016 ,46 （2 ）:379 −387 . （in Chinese with English abstract）[16] ZHANG Jiong,MA G D,MING R P,et al. Numerical study on seepage flow in pervious concrete based on 3D CT imaging[J]. Construction and Building Materials,2018,161:468 − 478. doi: 10.1016/j.conbuildmat.2017.11.149
[17] WEN F S,FAN H F,ZHAI S T,et al. Pore characteristics analysis and numerical seepage simulation of antifreeze permeable concrete[J]. Construction and Building Materials,2020,255:119310. doi: 10.1016/j.conbuildmat.2020.119310
[18] 董辉,罗潇,李智飞. 堆积碎石土细观孔隙空间特征对其渗透特性的定量影响[J]. 中南大学学报(自然科学版),2017,48(5):1367 − 1375. [DONG Hui,LUO Xiao,LI Zhifei. Quantitative influence of meso-porosity space features of aggregate gravel soil on its permeability characteristics[J]. Journal of Central South University (Science and Technology),2017,48(5):1367 − 1375. (in Chinese with English abstract)]
DONG Hui, LUO Xiao, LI Zhifei . Quantitative influence of meso-porosity space features of aggregate gravel soil on its permeability characteristics[J]. Journal of Central South University （Science and Technology）,2017 ,48 （5 ）:1367 −1375 . （in Chinese with English abstract）[19] 陈勋,尹升华,严荣富,等. 渗流作用下风化壳淋积型稀土矿细观孔隙结构演化特征[J]. 工程科学学报,2021,43(10):1283 − 1294. [CHEN Xun,YIN Shenghua,YAN Rongfu,et al. Evolution characteristics of mesoscopic pore structure of weathered crust elutiondeposited rare earth ore under solution seepage[J]. Chinese Journal of Engineering,2021,43(10):1283 − 1294. (in Chinese with English abstract)]
CHEN Xun, YIN Shenghua, YAN Rongfu, et al . Evolution characteristics of mesoscopic pore structure of weathered crust elutiondeposited rare earth ore under solution seepage[J]. Chinese Journal of Engineering,2021 ,43 （10 ）:1283 −1294 . （in Chinese with English abstract）[20] FONSECA J,SIM W W,SHIRE T,et al. Microstructural analysis of sands with varying degrees of internal stability[J]. Géotechnique,2014,64(5):405 − 411.
[21] WEI Yani,FAN Wen,YU Bo,et al. Characterization and evolution of three-dimensional microstructure of Malan loess[J]. Catena,2020,192:104585. doi: 10.1016/j.catena.2020.104585
[22] AN Ran,KONG Lingwei,ZHANG Xianwei,et al. Effects of dry-wet cycles on three-dimensional pore structure and permeability characteristics of granite residual soil using X-ray micro computed tomography[J]. Journal of Rock Mechanics and Geotechnical Engineering,2022,14(3):851 − 860. doi: 10.1016/j.jrmge.2021.10.004
[23] 梁越,代磊,魏琦. 基于透明土和粒子示踪技术的渗流侵蚀试验研究[J]. 岩土工程学报,2022,44(6):1133 − 1140. [LIANG Yue,DAI Lei,WEI Qi. Experimental study on seepage erosion based on transparent soil and particle tracing technology[J]. Chinese Journal of Geotechnical Engineering,2022,44(6):1133 − 1140. (in Chinese with English abstract)]
LIANG Yue, DAI Lei, WEI Qi . Experimental study on seepage erosion based on transparent soil and particle tracing technology[J]. Chinese Journal of Geotechnical Engineering,2022 ,44 （6 ）:1133 −1140 . （in Chinese with English abstract）[24] 张刚. 管涌现象细观机理的模型试验与颗粒流数值模拟研究[D]. 上海:同济大学,2007. [ZHANG Gang. Researches on meso-scale mechanism of piping failure by means of model test and PFC numerical simulation[D]. Shanghai:Tongji University,2007. (in Chinese with English abstract)]
ZHANG Gang. Researches on meso-scale mechanism of piping failure by means of model test and PFC numerical simulation[D]. Shanghai: Tongji University, 2007. （in Chinese with English abstract） [25] 谢定松,蔡红,魏迎奇,等. 应力状态下覆盖层不良级配砂砾石料渗透稳定特性试验研究[J]. 水利水电技术(中英文),2021,52(增刊2):446 − 450. [XIE Dingsong,CAI Hong,WEI Yingqi,et al. Experimental study on the seepage stability characteristics of poor gravel overburden under stress [J]. Water Resources and Hydropower Engineering,2021,52(Sup 2):446 − 450. (in Chinese with English abstract)]
XIE Dingsong, CAI Hong, WEI Yingqi, et al. Experimental study on the seepage stability characteristics of poor gravel overburden under stress [J]. Water Resources and Hydropower Engineering, 2021, 52（Sup 2）: 446 − 450. （in Chinese with English abstract） [26] 刘杰. 土的渗透稳定与渗流控制[M]. 北京:水利电力出版社,1992. [LIU Jie. The stability and control of seepage of soil[M]. Beijing:Water Resources and Electric Power Press,1992. (in Chinese)]
LIU Jie. The stability and control of seepage of soil[M]. Beijing: Water Resources and Electric Power Press, 1992. （in Chinese） [27] 王韦,沈景中. 砾土渗透变形(管涌)的研究[M]. 南京:南京水利科学研究院,1964. [WANG Wei,SHEN Jingzhong. Research on seepage deformation of sand and gravel soil (piping)[M]. Nanjing:Nanjing Institute of Water Conservancy,1964. (in Chinese)]
WANG Wei, SHEN Jingzhong. Research on seepage deformation of sand and gravel soil （piping）[M]. Nanjing: Nanjing Institute of Water Conservancy, 1964. （in Chinese） [28] 徐国建,沈扬,刘汉龙. 孔隙率、级配参数对粉土双轴压缩性状影响的颗粒流分析[J]. 岩土力学,2013,34(11):3321 − 3328. [XU Guojian,SHEN Yang,LIU Hanlong. Analysis of particle flow for impacts of granular parameters and porosity on silt’s properties under biaxial compression[J]. Rock and Soil Mechanics,2013,34(11):3321 − 3328. (in Chinese with English abstract)]
XU Guojian, SHEN Yang, LIU Hanlong . Analysis of particle flow for impacts of granular parameters and porosity on silt’s properties under biaxial compression[J]. Rock and Soil Mechanics,2013 ,34 （11 ）:3321 −3328 . （in Chinese with English abstract）[29] 尹升华,陈勋,刘超,等. 矿石颗粒级配对堆浸体系三维孔隙结构的影响[J]. 工程科学学报,2020,42(8):972 − 979. [YIN Shenghua,CHEN Xun,LIU Chao,et al. Effects of ore size distribution on the pore structure characteristics of packed ore beds[J]. Chinese Journal of Engineering,2020,42(8):972 − 979. (in Chinese with English abstract)]
YIN Shenghua, CHEN Xun, LIU Chao, et al . Effects of ore size distribution on the pore structure characteristics of packed ore beds[J]. Chinese Journal of Engineering,2020 ,42 （8 ）:972 −979 . （in Chinese with English abstract）[30] LIN Ke,TAKAHASHI A. Experimental investigations on suffusion characteristics and its mechanical consequences on saturated cohesionless soil[J]. Soils and Foundations,2014,54(4):713 − 730. doi: 10.1016/j.sandf.2014.06.024
-
图(10)
表(5)
计量
- 文章访问数: 1107
- PDF下载数: 145
- 施引文献: 0