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Study on slope stability weakening process along with infiltration by rainfall
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摘要: 天然降雨和高坝泄洪雾化雨入渗对大坝下游边坡有两方面影响，一是升高含水率使土体重度增加，导致其下滑力增加；二是升高土体含水率，降低土抗剪强度和阻滑力。因此，降雨入渗引起的滑坡时有发生。对此设计了室内人工降雨物理模型试验，分析研究砂土质边坡降雨入渗情况下，边坡内部水分扩散过程和规律以及暂态饱和区扩展过程，计算各入渗时刻边坡的安全系数，分析入渗发展对边坡稳定性变化过程及其特征的影响。试验分析结果表明：降雨入渗率先在边坡表面形成暂态饱和区，随着降雨持续，暂态饱和区逐渐扩大；雨强越大，降雨期间形成的暂态饱和区越大，边坡稳定安全系数的降幅就越大；试验得到了降雨入渗深度随降雨历时和强度变化的经验式。增大降雨强度会使试验砂土的含水率更接近于饱和含水率，但无法使砂土完全饱和。降雨入渗对边坡稳定性的影响不仅仅发生在降雨过程中，降雨停止后，水分入渗过程延续，边坡稳定性持续降低，水分入渗在一定的延后时间内继续威胁边坡安全。雨强为144 mm/h条件下边坡稳定安全系数在6 h时降到了最小值1.196，最大降幅达38.2%。Abstract: Natural rainfall and atomization rain will make infiltration into slope with a certain time process, which influences the slope stability in the downstream of high dam. The influence manifests in two aspects, on the one hand, the increase of water content increases the bulk density of the soil, resulting in an increase in the sliding force of slope; on the other hand, the soil moisture content increases, which makes the shear parameters of slope reduced. Engineering events caused by rainfall infiltration occur frequently. In the study, an indoor artificial rainfall physical model test was designed to study the process and law of water diffusion and the expansion process of transient saturation zone in the slope during rainfall infiltration of sand slope. The safety factor of slope was calculated to analyze the effect of rainfall infiltration process on slope stability. The test results showed that a transient saturated zone was formed firstly in the surface of the slope. As the rainfall continued, the transient saturation zone gradually expanded. The greater the rainfall intensity, the larger the transient saturation zone formed by the rainfall process, and the greater the reduction of the slope safety factor. The empirical formula of the water infiltration depth along with the rainfall duration and rainfall intensity was obtained. Increasing the rainfall intensity would make the water content of the test sand closer to the saturate water content, but the sand wouldn't completely saturate. The effect of rainfall infiltration in slope not only occurred during the rainfall process. After the rainfall stopped, the water infiltration process kept existing, the stability of the slope continued to decrease, and the water did harm to the slope in a certain delay time. In the case of rainfall intensity of 144 mm/h, the stability safety factor of the slope decreased to a minimum of 1.196 at 6 h, with a maximum decrease of 38.2%.
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图 5 降雨强度为72 mm/h的边坡含水率等值线
Figure 5. Contour map of slope moisture content with rainfall intensity of 72 mm/h
表 1 含水率升高响应时间
Table 1. Time of water content increasing
工况 降雨强度/
(mm·h-1)含水率升高响应时间/h 埋深10 cm处 埋深70 cm处 1 72 0.50 8 2 108 0.50 5 3 144 0.25 4 
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表 2 边坡极限含水率
Table 2. Extremum of water content
工况 降雨强度/
(mm·h-1)降雨阶段极限
含水率/%试验27 h极限
含水率/%1 72 27.5 12.8 2 108 27.8 14.6 3 144 28.3 17.8
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表 3 边坡稳定安全系数计算参数
Table 3. Calculation parameters
含水率/% 密度/(g·cm-3) 重度/(kN·m-3) Φ/° c/kPa 0~6 1.596 5 15.965 32.88 32.58 6~12 1.689 5 16.895 32.21 20.79 12~18 1.782 5 17.825 33.74 13.24 18~24 1.875 5 18.755 35.01 9.94 24~30 1.968 5 19.685 33.54 10.89
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表 4 试验过程边坡安全系数变化
Table 4. Slope safety factor change during test
工况 降雨强度/(mm·h-1) 初始安全系数 3 h时安全系数 3 h时降幅/% 最小安全系数 最大降幅/% 最小安全系数时刻 1 72 1.935 1.496 22.7 1.299 32.8 9 h 2 108 1.935 1.453 24.9 1.211 37.4 6 h 3 144 1.935 1.413 27.0 1.196 38.2 6 h
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[1] 苏建明, 李浩然.二滩水电站泄洪雾化对下游边坡的影响[J].水文地质工程地质, 2002(2): 22-24. doi: 10.3969/j.issn.1000-3665.2002.02.006 SU Jianming, LI Haoran. The effects of atomization by flood discharge on downstream slope of Ertan hydroelectric station[J]. Hydrogeology and Engineering Geology, 2002(2): 22-24. (in Chinese) doi: 10.3969/j.issn.1000-3665.2002.02.006 [2] SAMMORI T, TSUBOYAMA Y. Parametric study on slope stability with numerical simulation in consideration of seepage process[C]// Proceedings of 6th International Symposium on Landslides. Christchurch: Balkema Publishers, 1991: 539-544. [3] HUANG C C, YUIN S C. Experimental investigation of rainfall criteria for shallow slope failures[J]. Geomorphology, 2010, 120:326-338. doi: 10.1016/j.geomorph.2010.04.006 [4] TOHARI A, NISHIGAKI M, KOMATSU M, et al. Laboratory rainfall-induced slope failure with moisture content measurement[J]. Journal of Geotechnical and Geoenvironmental Engineering, ASCE, 2007, 133(5): 575-587. doi: 10.1061/(ASCE)1090-0241(2007)133:5(575) [5] CATANE S G, ZARCO M A H, CORDERO C J N, et al. Laboratory experiments on steady state seepage-induced landslides using slope models and sensors[J]. Science Diliman, 2011, 23(1): 17-30. http://d.old.wanfangdata.com.cn/OAPaper/oai_doaj-articles_6bde116acb1affd0d42af8763a473a80 [6] 张有天, 王镭, 陈平.有地表入渗的岩体渗流分析[J].岩石力学与工程学报, 1991, 10(2): 103-111. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=yslxygcxb200203033 ZHANG Youtian, WANG Lei, CHEN Ping. Anlysis of water percolation in rockmass due to surface infiltration[J]. Chinese Journal of Rock Mechanics and Engineering, 1991, 10(2): 103-111. (in Chinese) http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=yslxygcxb200203033 [7] 张有天, 刘中.降雨过程裂隙网络饱和非饱和非恒定渗流分析[J].岩石力学与工程学报, 1997, 16(4): 104-111. http://www.cnki.com.cn/Article/CJFDTOTAL-YSLX702.001.htm ZHANG Youtian, LIU Zhong. Saturated/unsaturated, unsteady seepage analysis of rock fractured networks due to the percolation of rainfall[J]. Chinese Journal of Rock Mechanics and Engineering, 1997, 16(4): 104-111. (in Chinese) http://www.cnki.com.cn/Article/CJFDTOTAL-YSLX702.001.htm [8] 王环玲, 徐卫亚, 童富国.泄洪雾雨区裂隙岩质边坡饱和-非饱和渗流场与应力场耦合分析[J].岩土力学, 2008(9): 2397-2403. doi: 10.3969/j.issn.1000-7598.2008.09.017 WANG Huanling, XU Weiya, TONG Fuguo. Coupled analysis of fracture rock mass slope saturated-unsaturated seepage field and stress field in flood discharge atomized rain area[J]. Rock and Soil Mechanics, 2008(9): 2397-2403. (in Chinese) doi: 10.3969/j.issn.1000-7598.2008.09.017 [9] 林鸿州.降雨诱发土质边坡失稳的试验与数值分析研究[D].北京: 清华大学, 2007. http://cdmd.cnki.com.cn/Article/CDMD-10003-2008088120.htm LIN Hungchou. The study on the mechanism and numerical analysis of rainfall-induced soil slope failure[D]. Beijing: Tsinghua University, 2007. (in Chinese) http://cdmd.cnki.com.cn/Article/CDMD-10003-2008088120.htm [10] 林鸿州, 于玉贞, 李广信, 等.降雨特性对土质边坡失稳的影响[J].岩石力学与工程学报, 2009, 28(1): 198-204. doi: 10.3321/j.issn:1000-6915.2009.01.026 LIN Hungchou, YU Yuzhen, LI Guangxin, et al. Influence of rainfall characteristics on soil slope failure[J]. Chinese Journal of Rock Mechanics and Engineering, 2009, 28(1): 198-204. (in Chinese) doi: 10.3321/j.issn:1000-6915.2009.01.026 [11] 李波.降雨条件下松散粉土边坡稳定性研究[D].黑龙江: 哈尔滨工业大学, 2009. http://cdmd.cnki.com.cn/Article/CDMD-10213-2011016333.htm LI Bo. Study on stability of loose sand slopes subjected to rainfall[D]. Heilongjiang: Harbin Institute of Technology, 2009. (in Chinese) http://cdmd.cnki.com.cn/Article/CDMD-10213-2011016333.htm [12] 孙永帅.降雨对边坡稳定性的模型试验及数值模拟研究[D].北京: 中国地质大学, 2012. http://cdmd.cnki.com.cn/Article/CDMD-11415-1012364896.htm SUN Yongshuai. Model test and numerical simulation study of slope instability induced by rainfall[D]. Beijing: China University of Geosciences, 2012. (in Chinese) http://cdmd.cnki.com.cn/Article/CDMD-11415-1012364896.htm [13] 钱家欢, 殷宗泽.土工原理与计算[M].北京:中国水利水电出版社, 1994: 320-324. QIAN Jiahuan, YIN Zongze. Geotechnical principle and calculation[M]. Beijing: China Water and Power Press, 1994: 320-324. (in Chinese) [14] 周辉.泄洪雾化的影响及其分区和分级防护初探[C]//中国水利学会水力学专业委员会, 中国水力发电工程学会水工水力学专业委员会, 国际水利工程与研究协会中国分会.第二届全国水力学与水利信息学学术大会论文集, 成都: 四川大学出版社, 2005: 6. http://cpfd.cnki.com.cn/Article/CPFDTOTAL-ZGSL200510003016.htm ZHOU Hui. Impact of flood discharge atomization and its zoning and classification protection[C]// Hydraulics Committee of China Water Conservancy Society, Hydraulic Hydraulics Committee of China Hydropower Engineering Society, China Branch of International Hydraulic Engineering and Research Association. Proceedings of the National Conference on Hydraulics and Hydraulic Informatics Hydraulics, Chengdu: Sichuan University Press, 2005: 6. (in Chinese) http://cpfd.cnki.com.cn/Article/CPFDTOTAL-ZGSL200510003016.htm -
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