Influence of rainfall on sliding modes of cutting slope of weathered granite stratum: Taking Yunxiao section in the Yunping freeway in Fujian for example
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摘要: 降雨引起路堑边坡的浅层局部滑动是工程中常见的现象，但其内在原因的研究尚不充分。为此，以福建省云平高速云霄段花岗岩风化层中的某两级路堑边坡为例，采用饱和和非饱和土抗剪强度理论，按照强度折减有限元方法分析了该边坡在一般工况、地下水渗流工况和降雨入渗工况下的滑动模式。结果表明：一般工况下该边坡滑动模式为深层整体滑动；地下水渗流作用可使边坡由深层滑动模式向浅层滑动模式转化；长时小或中等降雨作用下坡体内出现三道滑动面，且一级边坡内滑动面最先贯通，滑坡模式由深层整体滑动向浅层局部滑动演化。短时强降雨作用下仅在一级边坡内出现贯通的滑动面，即由整体滑动模式完全转变为浅层局部滑动模式。降雨工况越不利表现越为明显，与实际滑坡现象相吻合，且安全系数不满足规范要求，从而从理论上验证了该路堑边坡发生浅层局部滑动的必然性。此外，为避免花岗岩风化层路堑边坡在降雨入渗下发生浅层局部滑动，对假设的不同放坡方案进行了数值模拟分析。结果表明，适当放缓坡率可使一级边坡内不出现滑动面，滑坡模式仍为较深位置的整体滑动，且安全系数可得到有效提高，使其满足规范要求。因此，实践中，采用文中方法对设计的类似地层中的路堑边坡事先进行降雨入渗影响下的模拟分析极为必要。将使放坡坡率更为科学合理，可在确保边坡整体稳定性的同时，极大降低其发生浅层局部滑动的可能性。Abstract: It is a common phenomenon that rainfall may cause locally shallow sliding of cutting slopes, but the study on the immanent cause is still insufficient. Take a two-grade cutting slope in the weathered granite stratum in Yunxiao section in the Yunping freeway in Fujian as an example, the shear strength theories of saturated soil and unsaturated soil and the strength reduction method of finite element were adopted to study the sliding modes of cutting slope under general working condition, groundwater seepage, and rainfall infiltration. The results show that the sliding mode of the slope exhibits the globally deep sliding under the general working condition. The sliding mode turns to be the shallow sliding from the deep sliding under groundwater seepage. Three slip surfaces may develop in the slope after a long-term light and/or moderate rainfalls, and the slip surface within the first-grade slope runs through firstly so that the sliding mode evolves into the locally shallow sliding from the globally deep sliding. A run-through slip surface only occurs within the first-grade slope after short-term strong rainfalls, i.e., the sliding mode completely turns to be the locally shallow one from the globally sliding one, and the more unfavorable the working condition of a rainfall is, the more remarkable it exhibits. It also agrees well with the phenomenon of the practical landslide, and the safety factor cannot meet the requirement of the specification, and thereby the inevitability of the locally shallow sliding of the cutting slope was theoretically verified. In addition, to avoid the occurrence of the locally shallow sliding of cutting slopes in the weathered granite stratum under the infiltration of rainfalls, various hypothetical schemes were numerically modeled. The results show that no slip surface will occur within the first-grade slope if it is sloped at an appropriate gentle slope, and as a result, the sliding mode is still a globally sliding in a deeper location and the safety factor may be effectively enhanced to meet the requirement of the specification. Therefore, in practice, it is extremely necessary to carry out the simulation analysis of a designed cutting slope in similar stratum under the infiltration of rainfall beforehand. Thus, the gradient of sloping will be more scientific and reasonable, so probability of the occurrence of the locally shallow sliding may be significantly reduced.
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图 6 一般工况水平位移等值云图
Figure 6. Horizontal displacement contours under general working condition
图 10 长时小雨工况水平位移等值云图
Figure 10. Horizontal displacement contours under long-term light rainfall
图 13 工况3水平位移等值云图
Figure 13. Horizontal displacement contours under Working Condition 3
表 1 土工参数
Table 1. Geotechnical properties of soils
土层编号 γ/(kN·m−3) γd/(kN·m−3) E/kPa υ c/kPa $\varphi $/(°) c'/kPa $\varphi' $/(°) 7-210 19.5 15.6 8000 0.28 24.9 16.8 22.4 20.6 7-211 20.0 16.5 10 000 0.30 28.9 17.8 24.6 22.2 
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表 2 不同降雨工况边坡稳定安全系数
Table 2. Safety factors of slope under different rainfall conditions
工况 降雨强度/(mm·h−1） 降雨历时/h 安全系数 1 20 4 1.152 2 30 4 1.113 3 40 4 1.091 4 40 3 1.106 5 40 2 1.140
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ZIENKIEWICZ O C, HUMPHESON C, LEWIS R W. Associated and non-associated visco-plasticity and plasticity in soil mechanics[J]. Geotechnique,1975,25(4):671 − 689. doi: 10.1680/geot.1975.25.4.671 赵尚毅, 郑颖人, 时卫民, 等. 用有限元强度折减法求边坡稳定安全系数[J]. 岩土工程学报,2002,24(3):343 − 346. [ZHAO Shangyi, ZHENG Yingren, SHI Weimin, et al. Analysis on safety factor of slope by strength reduction FEM[J]. Chinese Journal of Geotechnical Engineering,2002,24(3):343 − 346. (in Chinese with English abstract) doi: 10.3321/j.issn:1000-4548.2002.03.017 郑颖人, 赵尚毅, 宋雅坤. 有限元强度折减法研究进展[J]. 后勤工程学院学报,2005,21(3):1 − 6. [ZHENG Yingren, ZHAO Shangyi, SONG Yakun. Advance of study on the strength reduction finite element method[J]. Journal of Logistical Engineering University,2005,21(3):1 − 6. (in Chinese with English abstract) doi: 10.3969/j.issn.1672-7843.2005.03.001 李湛, 栾茂田, 刘占阁, 等. 渗流作用下边坡稳定性分析的强度折减弹塑性有限元法[J]. 水利学报,2006,37(5):554 − 559. [LI Zhan, LUAN Maotian, LIU Zhange, et al. Elasto-plastic FEM for embankment stability analysis under the condition of seepage based on the technique of shear strength reduction[J]. Journal of Hydraulic Engineering,2006,37(5):554 − 559. (in Chinese with English abstract) doi: 10.3321/j.issn:0559-9350.2006.05.006 张昊, 余巍伟, 林杭, 等. 不同安全系数对应的边坡滑动面位置分析[J]. 岩土力学,2012,33(2):449 − 452. [ZHANG Hao, YU Weiwei, LIN Hang, et al. Analysis of location distribution of slope slip plane with different factors of safety[J]. Rock and Soil Mechanics,2012,33(2):449 − 452. (in Chinese with English abstract) doi: 10.3969/j.issn.1000-7598.2012.02.021 刘明维, 郑颖人. 基于有限元强度折减法确定滑坡多滑动面方法[J]. 岩石力学与工程学报,2006,25(8):1544 − 1549. [LIU Mingwei, ZHENG Yingren. Determination methods of multi-slip surfaces landslide based on strength reduction fem[J]. Chinese Journal of Rock Mechanics and Engineering,2006,25(8):1544 − 1549. (in Chinese with English abstract) doi: 10.3321/j.issn:1000-6915.2006.08.005 毕港, 陈征宙, 姜玉平, 等. 一种边坡多滑动面搜索的新方法[J]. 水文地质工程地质,2011,38(6):24 − 28. [BI Gang, CHEN Zhengzhou, JIANG Yuping, et al. A new method for searching all possible circular slips of a slope[J]. Hydrogeology & Engineering Geology,2011,38(6):24 − 28. (in Chinese with English abstract) 李小春, 袁维, 白冰, 等. 基于局部强度折减法的边坡多滑面分析方法及应用研究[J]. 岩土力学,2014(3):847 − 854. [LI Xiaochun, YUAN Wei, BAI Bing, et al. Analytic approach of slope multi-slip surfaces based on local strength reduction method and its application[J]. Rock and Soil Mechanics,2014(3):847 − 854. (in Chinese with English abstract) LIN H, CAO P, GONG F Q, et al. Directly searching method for slip plane and its influential factors based on critical state of slope[J]. Journal of Central South University of Technology,2009,16(1):131 − 135. doi: 10.1007/s11771-009-0022-6 FREDLUND D G, RAHARDJO H. 非饱和土力学[M]. 陈仲颐, 张在明, 陈愈炯, 等. 译. 北京: 中国建筑工业出版社, 1997.FREDLUND D G, RAHARDJO H. Soil mechanics for unsaturated soils[M]. CHEN Zhongyi, ZHANG Zaiming, CHEN Yujiong, et al. translator. Beijing: China Building Industry, 1997. (in Chinese with English abstract) ALONSO E, GENS A, LLORET A, et al. Effect of rain infiltration on the stability of slopes[J]. Unsaturated Soils J.,1995,1:241 − 249. CHO S E, LEE S R. Instability of unsaturated soil slopes due to infiltration[J]. Computers and Geosciences,2001,28(3):185 − 208. 黄盛锋, 陈志波, 郑道哲. 基于灰色关联度法和强度折减法的边坡稳定性影响因素敏感性分析[J]. 中国地质灾害与防治学报,2020,31(3):35 − 40. [HUANG Shengfeng, CHEN Zhibo, ZHENG Daozhe. Sensitivity analysis of factors influencing slope stability based on grey correlation and strength reduction method[J]. The Chinese Journal of Geological Hazard and Control,2020,31(3):35 − 40. (in Chinese with English abstract) 陈子玉, 宋彦辉, 严豪, 等. 双参数强度折减法研究中存在的问题分析[J]. 水文地质工程地质,2019,46(2):125 − 132. [CHEN Ziyu, SONG Yanhui, YAN Hao, et al. Analyses of the existing problems in the double parameters reduction method[J]. Hydrogeology & Engineering Geology,2019,46(2):125 − 132. (in Chinese with English abstract) 中华人民共和国交通运输部. 公路路基设计规范: JTG D 30—2015[S]. 北京: 人民交通出版社, 2015.Specifications for design of highway subgrades: JTG D 30—2015[S]. Beijing: China Communications Press, 2015. (in Chinese) 陈丽刚. 基于ABAQUS渗流与应力耦合作用的边坡稳定性分析[D]. 郑州: 郑州大学, 2010.CHEN Ligang. The slope stability analysis of taking into account the seepage and stress coupling effect based on ABAQUS[D]. Zhengzhou: Zhengzhou University, 2010. (in Chinese with English abstract) 费康, 彭劼. ABAQUS岩土工程实例详解[M]. 北京: 人民邮电出版社, 2017.FEI Kang, PENG Jie. Detailed explanation of geotechnical engineering cases using ABAQUS[M]. Beijing: Posts & Telecom Press, 2017. (in Chinese) 徐翔, 王义兴, 方正. 降雨和库水联合作用下边坡稳定性变化规律[J]. 中国地质灾害与防治学报,2019,30(2):51 − 58. [XU Xiang, WANG Yixing, FANG Zheng. Analysis on stability of a slope under rainfall and reservoir water level variation[J]. The Chinese Journal of Geological Hazard and Control,2019,30(2):51 − 58. (in Chinese with English abstract) -
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