Reliability Analysis of Stability of Fill Slope
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摘要: 为了系统地建立填土边坡稳定性的可靠度分析方法, 首先, 在可靠度分析原理的基础上, 对填土边坡的不确定性进行了讨论; 然后, 建立了多变量影响下填土边坡可靠度分析的基本流程; 最后, 以广西平乐县二塘锰矿区典型填土边坡为例, 基于GeoStudio软件, 应用所提出的分析流程对典型填土边坡的可靠度指标进行了计算, 通过"安全概率"对边坡的安全性进行了评价.研究结果表明: (1)填土边坡的不确定性包括内部结构和环境因素两方面, 前者不确定因素来自于填土土体不确定性和边坡的几何特征不确定性, 后者不确定性因素来自于降雨、地震和人工加载等; (2)可靠度分析的基本流程为填土边坡系统不确定性分析、建立可靠度极限状态方程、求解可靠度指标和边坡安全性评价; (3)广西平乐二塘锰矿填土边坡敏感性因素排序为: 内摩擦角Φ>黏聚力C>车辆荷载F; (4)考虑50年一遇极值降雨过程, 稳定性系数在降雨12 h达到最小, 其可靠度指标(β)为8.79, 破坏概率为0.根据《滑坡防治工程设计与施工技术规范》所规定的安全系数, 填土边坡的安全概率为69.84%.Abstract: In order to analyze reliability of the stability of fill slopes, first, uncertain factors of stability of slope are discussed on the basis of the reliability theory. Then, the basic process of reliability analysis of fill slope is established, considering multi-variables. Finally, we apply the proposed method to analyze typical fill slope in manganese mine located at Ertang village, Pingle county, Guangxi. Results show that the fill slope uncertainties include two aspects, namely, internal structure and environmental factors. The former is due to the uncertainty of soil and slope geometric characteristics, and the latter is due to the rainfall, earthquakes, artificial load and so on. The reliability analysis contains three steps including analyzing uncertainty of fill slope, establishing the equation of reliability analysis, calculating reliability index and evaluating slope safety. The sensitivity factors for analyzing slope stability is internal friction angle Φ > cohesion C > vehicle load F. When Considering the maximum rainfall of 50 years return period, the stability is lowest at 12 h in one rain course. Its reliability index (β) is 8.79 and the failure probability is 0. According to the safety factor of criterion, the safe probability of the fill slope is 69.84%.
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Key words:
- slope stability /
- reliability analysis /
- system uncertainty /
- safety probability /
- engineering geology
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图 1 不同施工技术填土结构特征(据陈团结和贾润萍, 2002)
a.分层压实填土结构;b.强夯法填土结构;c.不同压实技术填土压实度分布情况;d.平乐二塘锰矿填土压实度和黏聚力关系
Fig. 1. Fill soil structure of different compaction methods
表 1 平乐二塘锰矿区典型填土边坡可靠度分析参数
Table 1. Typical fill slope reliability analysis parameters in Ertang Manganese Mine, Pingle
统计特征 填土物理参数 降雨量 车辆加载kN 粘聚力C(KPa) 重度γ(kN/m3) Φ(°) 次降雨量重现期(mm) 降雨强度(mm/h) 均值 23 17.4 19.5 20 a/250 20 a/15 250.7 50 a/300 50 a/20 方差 1.80 1.50 1.50 51.3 概率模型 正态分布 正态分布 正态分布 极值分布 极值分布 正态分布 表 2 填土边坡不同滑面最小稳定性系数结果比较
Table 2. Minimum stability coefficient of fill slope with different slip surface
项目名称 本文(抛物线)法 圆弧法 ordinary Bishop 最小稳定性系数 1.15 1.39 1.50 滑动面形状 抛物线形 圆弧形 表 3 50年重现期极值雨量边坡稳定性均值
Table 3. Mean stability coefficient of fill slope with rainfall of 50-year return period
时间(h) 计算方法 ordinary Bishop Janbu M-P 0 1.189 1.251 1.152 1.245 1 1.161 1.221 1.128 1.215 4 1.143 1.200 1.112 1.195 12 1.059 1.106 1.036 1.102 24 1.076 1.137 1.048 1.132 36 1.093 1.176 1.057 1.169 48 1.100 1.183 1.063 1.176 -
Chai, B., Yin, K.L., Wang, Y., et al., 2007. Sensitivity Analysis of Landslide Stability Based on Distribution Models of Influencing Factors. Rock and Soil Mechanics, 28(12): 2624-2628 (in Chinese with English abstract). Chen, T.J., Jia, R.P., 2002. Correct Application of Subgrade Compaction Method and Reasonable Cutting Ring Sampling Depth. Journal of Highway and Transportation Research and Development, 19(6): 45-47, 51 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-GLJK200206012.htm Chowdhury, R.N., Xu, D.W., 1995. Geotechnical System Reliability of Slopes. Reliability Engineering and System Safety, 47(3): 141-151. doi: 10.1016/0951-8320(94)00063-T Guo, T., Li, A.Q., Zhao, D.L., 2008. Multiple-Peaked Probabilistic Vehicle Load Model for Highway Bridge Reliability Assessment. Journal of Southeast University (Natural Science Edition), 38(5): 763-766 (in Chinese with English abstract). http://d.wanfangdata.com.cn/Periodical/dndxxb200805005 Li, Y.Y., Yin, K.L., Chai, B., et al., 2008. Study on Statistical Rule of Shear Strength Parameters of Soil in Landslide Zone in Three Gorges Reservoir Area. Rock and Soil Mechanics, 29(5): 1419-1425 (in Chinese with English abstract). http://d.wanfangdata.com.cn/Periodical/ytlx200805053 Luo, W.Q., Zhang, Z.Y., Huang, R.Q., et al., 2002. Advances in the Research on Reliability on Slope System. Earth Science Frontiers, 7(S2): 105-111 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-DXQY2000S2016.htm Mei, G., Qin, Q., Lin, D.J., 2003. Bi-Modal Probabilistic Model of Highway and Bridge Vehicle Loads. Journal of Tsinghua University (Sci. & Tech. ), 43(10): 1394-1396, 1404 (in Chinese with English abstract). http://d.wanfangdata.com.cn/periodical/qhdxxb200310026 Sun, D.M., Zhu, Y.M., Zhang, M.J., 2007. Water-Air Two-Phase Flow Model for Numerical Analysis of Rainfall Infiltration. Shuili Xuebao, 38(2): 150-156 (in Chinese with English abstract). http://www.cqvip.com/QK/90347X/200702/23952013.html Wang, J.Y., Li, H.F., Duan, W.J., et al., 2012. Research on Rainfall Characteristics through Typical Forest Community. Research of Soil and Water Conservation, 19(1): 56-59 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-STBY201201013.htm Yao, Y.W., Chen, D.W., 1994. Analysis of Reliability Index in Slope Stability. Chinese Journal of Geotechnical Engineering, 16(2): 80-87 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-CQJT2007S1019.htm Zhao, H.R., Xia, B.C., Jiang, X.D., 2011. Characteristics of Precipitation Change in Guilin Last 50 Years. Journal of Guilin University of Technology, 31(2): 202-206 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-GLGX201102008.htm Zhu, W., Chen, X.D., Zhong, X.C., 2006. Observation and Analysis of Rainfall Infiltration. Rock and Soil Mechanics, 27(11): 1873-1879 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-YTLX200611002.htm 柴波, 殷坤龙, 汪洋, 等, 2007. 基于影响因素分布模型的滑坡稳定性敏感分析. 岩土力学, 28(12): 2624-2628. doi: 10.3969/j.issn.1000-7598.2007.12.027 陈团结, 贾润萍, 2002. 填土路基压实方法与环刀法取样深度中的误区. 公路交通科技, 19(6): 45-47, 51. doi: 10.3969/j.issn.1002-0268.2002.06.013 郭彤, 李爱群, 赵大亮, 2008. 用于公路桥梁可靠性评估的车辆荷载多峰分布概率模型. 东南大学学报(自然科学版), 38(5): 763-766. doi: 10.3321/j.issn:1001-0505.2008.05.005 李远耀, 殷坤龙, 柴波, 等, 2008. 三峡库区滑带土抗剪强度参数的统计规律研究. 岩土力学: 29(5): 1419-1425. doi: 10.3969/j.issn.1000-7598.2008.05.053 罗文强, 张倬元, 黄润秋, 等, 2002. 斜坡系统可靠性分析研究. 地学前缘, 7(S2): 105-111. https://www.cnki.com.cn/Article/CJFDTOTAL-DXQY2000S2016.htm 梅刚, 秦权, 林道锦, 2003. 公路桥梁车辆荷载的双峰分布概率模型. 清华大学学报(自然科学版), 43(10): 1394-1396, 1404. doi: 10.3321/j.issn:1000-0054.2003.10.026 孙冬梅, 朱岳明, 张明进, 2007. 降雨入渗过程的水-气二相流模型研究. 水利学报, 38(2): 150-156. doi: 10.3321/j.issn:0559-9350.2007.02.004 王金叶, 李海防, 段文军, 等, 2012. 漓江上游典型森林群落内外降雨特征研究. 水土保持研究, 19(1): 56-59. https://www.cnki.com.cn/Article/CJFDTOTAL-STBY201201013.htm 姚耀武, 陈东伟, 1994. 土坡稳定可靠度分析. 岩土工程学报, 16(2): 80-87. doi: 10.3321/j.issn:1000-4548.1994.02.010 赵华荣, 夏北成, 江学顶, 2011. 桂林市近50年降雨变化特征分析. 桂林理工大学学报, 31(2): 202-206. doi: 10.3969/j.issn.1674-9057.2011.02.006 朱伟, 陈学东, 钟小春, 2006. 降雨入渗规律的实测与分析. 岩土力学, 27(11): 1873-1879. doi: 10.3969/j.issn.1000-7598.2006.11.003