Effect of colluvial soil slope fracture’s anisotropy characteristics on rainwater infiltration process
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摘要: 采用有限元软件Geo-Slope中的SEEP/W模块分析了裂隙深度、渗透系数比、裂隙角度与裂隙数对雨水入渗过程的影响,结合非饱和渗流理论研究了裂隙渗流各向异性对边坡稳定性的影响。分析结果表明:降雨1、7 d时,1 m裂隙深度内最大孔隙水压力分别为9.69、9.70 kPa,雨水沿裂隙底部向下的入渗深度分别为0.5、1.5 m,裂隙内孔隙水压力随降雨的持续迅速增大,直至由负压力转变为正压力; 裂隙深度越大,裂隙内孔隙水压力越大,降雨停止时刻相应的入渗深度也越大,饱和区域的大小与裂隙深度正相关; 当渗透系数比为1时,裂隙范围内最大渗透系数为1.51×10-7 m・s-1,此时沿裂隙方向渗透系数小于降雨强度,降雨入渗过程受土体渗透系数控制,而当沿裂隙方向渗透系数大于降雨强度时,雨水入渗过程受降雨强度控制; 裂隙角度越小,在裂隙深度范围内的最大孔隙水压力越大,且出现正孔隙水压力的深度也越大,而边坡表层饱和区范围越小; 无裂隙存在时,降雨后边坡内部仍保持负压力状态,无饱和区存在,有裂隙存在时,雨水沿裂隙下渗并在边坡内部形成饱和正压力区,1~5条裂隙形成的饱和区面积分别为16.4、34.7、60.9、75.6、110.7 m2,饱和区面积与裂隙数呈乘幂关系,且随着裂隙数的增加,雨水对渗流场的影响范围与程度增大,长裂隙的集中分布是引起边坡内部大面积连通型饱和区出现与地下水位升高的直接原因。Abstract: The SEEP/W module of the finite element software Geo-Slope was used to analyze the effects of fracture depth, permeability coefficient ratio, fracture angle and fracture number on the rainwater infiltration process. The effect of fracture seepage anisotropy on slope stability was studied along with the unsaturated seepage theory. Analysis result shows that when the rainfall duration is 1 and 7 d, respectively, the maximum pore water pressure in a 1 m fissure is 9.69 and 9.70 kPa, respectively, and the rainwater infiltration depth along the bottom of the fracture is 0.5 and 1.5 m, respectively. The pore water pressure in a fracture increases rapidly with the rainfall until it changes from a negative pressure to a positive pressure. The greater the fracture depth, the greater the pore water pressure in the fracture, and the greater the infiltration depth is when rainfall stops. The size of the saturated area is positively correlated with the fracture depth. When the permeability coefficient ratio is 1, the maximum permeability coefficient in the fracture range is 1.51×10-7 m・s-1. At this moment, the permeability coefficient along the fracture direction is less than the rainfall intensity, and the infiltration process is controlled by the soil permeability coefficient. When the fracture permeability coefficient along the fracture direction is larger than the rainfall intensity, the infiltration process is controlled by the rainfall intensity. The smaller the fracture angle, the greater the maximum pore water pressure in the fracture depth range, the greater the depth of the positive pore water pressure, and the smaller the range of surface saturation zone is. When there is no fracture, the slope still maintains a negative pressure state after rainfall, and there is no saturation zone. When there is a fracture, the rainwater infiltrates along the fracture and forms a saturated positive pressure zone inside the slope. The areas of the saturated zones formed by 1-5 fractures are16.4, 34.7, 60.9, 75.6 and 110.7 m2, respectively. A power relation exists between the saturation area and fracture number. The influence range and degree of rainwater on the seepage field increase with the increase of fracture number. The concentration distribution of long fractures directly forms a large connected saturated zone and raises groundwater. 1 tab, 14 figs, 33 refs.
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Key words:
- subgrade engineering /
- slope stability /
- fracture /
- anisotropy /
- rainwater infiltration
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[1] 詹良通,李 鹤,陈云敏,等.东南沿海残积土地区降雨诱发型滑坡预报雨强-历时曲线的影响因素分析[J].岩石力学,2012,33(3):872-880,886. ZHAN Liang-tong, LI He, CHEN Yun-min, et al. Parametric analyses of intensity-duration curve for predicting rainfall-induced landslides in residual soil slope in southeastern coastal areas of China[J]. Rock and Soil Mechanics, 2012, 33(3): 872-880, 886.(in Chinese) [2] PENG Tao, WANG Shi-jie. Effects of land use, land cover and rainfall regimes on the surface runoff and soil loss on karst slopes in southwest China[J]. Catena, 2012, 90: 53-62. [3] BORJA R I, WHITE J A. Continuum deformation and stability analyses of a steep hillside slope under rainfall infiltration[J]. Acta Geotechnica, 2010, 5(1): 1-14. [4] 肖治宇,陈昌富,杨剑祥.非饱和残坡积土强度随含水量变化试验研究[J].湖南大学学报:自然科学版,2010,37(10):20-24. XIAO Zhi-yu, CHEN Chang-fu, YANG Jian-xiang. Experimental studies of the strength variation of unsaturated residual soil with different water contents[J]. Journal of Hunan University: Natural Sciences, 2010, 37(10): 20-24.(in Chinese) [5] YE Zu-yang, JIANG Qing-hua, ZHOU Chuang-bing, et al. Numerical analysis of unsaturated seepage flow in two-dimensional fracture networks[J]. International Journal of Geomechanics, 2016, 17(5): 04016118-1-11. [6] 袁俊平,蔺彦玲,丁 鹏,等.裂隙诱导各向异性对边坡降雨入渗的影响[J].岩土工程学报,2016,38(1):76-82. YUAN Jun-ping, LIN Yan-ling, DING Peng, et al. Influence of anisotropy induced by fissures on rainfall infiltration of slopes[J]. Chinese Journal of Geotechnical Engineering, 2016, 38(1): 76-82.(in Chinese) [7] 鞠 杨,张钦刚,杨永明,等.岩体粗糙单裂隙流体渗流机制的实验研究[J].中国科学:技术科学,2013,43(10):1144-1154. JU Yang, ZHANG Qin-gang, YANG Yong-ming, et al. An experimental investigation on the mechanism of fluid flow through single rough fracture of rock[J]. Scientia Sinica: Technologica, 2013, 43(10): 1144-1154.(in Chinese) [8] 刘泉声,吴月秀,刘 滨.应力对裂隙岩体等效渗透系数影响的离散元分析[J].岩石力学与工程学报,2011,30(1):176-183. LIU Quan-sheng, WU Yue-xiu, LIU Bin. Discrete element analysis of effect of stress on equivalent permeability of fractured rockmass[J]. Chinese Journal of Rock Mechanics and Engineering, 2011, 30(1): 176-183.(in Chinese) [9] 陈必光,宋二祥,程晓辉.二维裂隙岩体渗流传热的离散裂隙网络模型数值计算方法[J].岩石力学与工程学报,2014,33(1):43-51. CHEN Bi-guang, SONG Er-xiang,CHENG Xiao-hui. A numerical method for discrete fracture network model for flow and heat transfer in two-dimensional fractured rocks[J]. Chinese Journal of Rock Mechanics and Engineering, 2014, 33(1): 43-51.(in Chinese) [10] LEUNG C T O, ZIMMERMAN R W. Estimating the hydraulic conductivity of two-dimensional fracture networks using network geometric properties[J]. Transport in Porous Media, 2012, 93(3): 777-797. [11] 薛娈鸾,陈胜宏.岩石裂隙渗流与法向应力耦合的复合单元模型[J].岩石力学与工程学报,2007,26(增1):2613-2619. XUE Luan-luan, CHEN Sheng-hong. Composite element model of seepage-normal stress coupling for rock fractures[J]. Chinese Journal of Rock Mechanics and Engineering, 2007, 26(S1): 2613-2619.(in Chinese) [12] 陈胜宏,王鸿儒,熊文林.节理面渗流性质的探讨[J].武汉水利电力学院学报,1989,22(1):53-60. CHEN Sheng-hong, WANG Hong-ru, XIONG Wen-lin. Study of the seepage characteristics of joint surface[J]. Journal of Wuhan University of Hydraulic and Electric Engineering, 1989, 22(1): 53-60.(in Chinese) [13] 霍吉祥,宋汉周,杜京浓,等.表面反应和扩散迁移联合控制的粗糙单裂隙渗流-溶解耦合模型[J].岩石力学与工程学报,2015,34(5):1013-1021. HUO Ji-xiang, SONG Han-zhou, DU Jing-nong, et al. Coupled fluid flow and chemical dissolution model based on surface reaction and mass transfer control in a rough fracture[J]. Chinese Journal of Rock Mechanics and Engineering, 2015, 34(5): 1013-1021.(in Chinese) [14] 速宝玉,张文捷,盛金昌,等.渗流-化学溶解耦合作用下岩石单裂隙渗透特性研究[J].岩土力学,2010,31(11):3361-3366. SU Bao-yu, ZHANG Wen-jie, SHENG Jin-chang, et al. Study of permeability in single fracture under effects of coupled fluid flow and chemical dissolution[J]. Rock and Soil Mechanics, 2010, 31(11): 3361-3366.(in Chinese) [15] SONG Fu-quan, HU Xiao, JI Kai, et al. Effect of fluid-solid coupling on shale mechanics and seepage laws[J]. Natural Gas Industry B, 2018(5): 41-47. [16] 黄诗冰,刘泉声,程爱平,等.低温裂隙岩体水-热耦合模型研究及数值分析[J].岩土力学,2018,39(2):735-744. HUANG Shi-bing, LIU Quan-sheng, CHENG Ai-ping, et al. A coupled hydro-thermal model of fractured rock mass under low temperature and its numerical analysis[J]. Rock and Soil Mechanics, 2018, 39(2): 735-744.(in Chinese) [17] ZENG Yang, KANG Xiao-dong, XIE Xiao-qing, et al. Studies on seepage law considering stratigraphic dips[J]. Petroleum, 2017, 3(4): 470-475. [18] LI Yi, CHEN Yi-feng, ZHANG Gui-jing, et al. A numerical procedure for modeling the seepage field of water-sealed underground oil and gas storage caverns[J]. Tunnelling and Underground Space Technology, 2017, 66: 56-63. [19] 付宏渊,曾 铃,蒋中明,等.降雨条件下公路边坡暂态饱和区发展规律[J].中国公路学报,2012,25(3):59-64. FU Hong-yuan, ZENG Ling, JIANG Zhong-ming, et al. Developing law of transient saturated areas of highway slope under rainfall conditions[J]. China Journal of Highway and Transport, 2012, 25(3): 59-64.(in Chinese) [20] 曾 铃,史振宁,付宏渊,等.降雨入渗对边坡暂态饱和区分布特征的影响[J].中国公路学报,2017,30(1):25-34. ZENG Ling, SHI Zhen-ning, FU Hong-yuan, et al. Influence of rainfall infiltration on distribution characteristics of slope transient saturated zone[J]. China Journal of Highway and Transport, 2017, 30(1): 25-34.(in Chinese) [21] 樊有维,章 羽,金雪莲,等.降雨对均质各向异性土质边坡稳定性的影响[J].岩土力学,2006,27(增):1097-1102. FAN You-wei, ZHANG Yu, JIN Xue-lian, et al. Effect of rainfall on stability of anisotropic soil slope[J]. Rock and Soil Mechanics, 2006, 27(S): 1097-1102.(in Chinese) [22] OU Su-bei, WANG Lian-guo, WANG Pei-pei, et al. Numerical analysis of seepage flow characteristic of collapse column under the influence of mining[J]. International Journal of Mining Science and Technology, 2013, 23(2): 237-244. [23] 殷宗泽,徐 彬.反映裂隙影响的膨胀土边坡稳定性分析[J].岩土工程学报,2011,33(3):454-459. YIN Zong-ze, XU Bin. Slope stability of expansive soil under fissure influence[J]. Chinese Journal of Geotechnical Engineering, 2011, 33(3): 454-459.(in Chinese) [24] LIU Shi-liang, LI Wen-ping, WANG Qi-qing, et al. Numerical simulation on crack propagation of rock mass with a single crack under seepage water pressure[J]. Advances in Mechanical Engineering, 2017, 9(10): 1-12. [25] WANG Zhen-zhi, PAN Jie-nan, HOU Quan-lin, et al. Anisotropic characteristics of low-rank coal fractures in the Fukang Mining area, China[J]. Fuel, 2018, 211: 182-193. [26] 蒋中明,曾 铃,付宏渊,等.极端久雨条件下软岩边坡动态稳定性分析[J].中国公路学报,2014,27(2):27-34. JIANG Zhong-ming, ZENG Ling, FU Hong-yuan, et al. Dynamic stability analysis of soft rock slope due to extremely prolonged rainfall[J]. China Journal of Highway and Transport, 2014, 27(2): 27-34.(in Chinese) [27] 蒋中明,唐 静,谢 刚,等.汝郴高速公路软岩边坡岩体渗透性现场压水试验研究[J].公路与汽运,2010(6):101-104. JIANG Zhong-ming, TANG Jing, XIE Gang, et al. Water pressure test of rock permeability of slope in Ruchen Expressway[J]. Highway and Automotive Application, 2010(6): 101-104.(in Chinese) [28] 邝美娟,谢红霞,隋 兵,等.湖南省近50年降雨特征分析[J].水土保持研究,2013,20(5):145-149. KUANG Mei-juan, XIE Hong-xia, SUI Bing, et al. Analysis on spatiotemporal characteristics of precipitation in Hunan Province from 1961 to 2010[J]. Research of Soil and Water Conservation, 2013, 20(5): 145-149.(in Chinese) [29] WU Xin-liang, WEI Yu-jie, WANG Jun-guang, et al. Effects of soil type and rainfall intensity on sheet erosion processes and sediment characteristics along the climatic gradient in central-south China[J]. Science of the Total Environment, 2018, 621: 54-66. [30] 殷宗泽,袁俊平,韦 杰.论裂隙对膨胀土边坡稳定的影响[J].岩土工程学报,2012,34(12):2155-2161. YIN Zong-ze, YUAN Jun-ping, WEI Jie. Influences of fissures on slope stability of expansive soil[J]. Chinese Journal of Geotechnical Engineering, 2012, 34(12): 2155-2161.(in Chinese) [31] 刘华强,殷宗泽.裂缝对膨胀土抗剪强度指标影响的试验研究[J].岩土力学,2010,31(3):727-731. LIU Hua-qiang, YIN Zong-ze. Test study of influence of fracture evolution on strength parameters of expansive soil[J]. Rock and Soil Mechanics, 2010, 31(3): 727-731.(in Chinese) [32] MUNKHOLM L J, HECK R J, DEEN B, et al. Relationship between soil aggregate strength, shape and porosity for soils under different long-term management[J]. Geoderma, 2016, 268: 52-59. [33] FREDLUND D G, MORGENSTERN N R, WIDGER R A. The shear strength of unsaturated soils[J]. Canadian Geotechnical Journal, 1978, 15(3): 313-321.
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