COMSOL MULTIPHYSIC BASED CALCULATION MODEL OF CRITICAL RAINFALL THRESHOLD FOR RAINFALL-INDUCED LANDSLIDE—A CASE STUDY OF KARAHAYISU LANDSLIDE IN XINYUAN COUNTY, XINJIANG
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摘要: 本文以新源县喀拉海依苏滑坡隐患体为研究案例,采用COMSOL Multiphysics数值模拟有限元软件,建立了基于非饱和渗流理论与Mohr-Coulomb准则的滑坡稳定性计算模型。根据数值模拟结果得到研究区滑坡体原始应力分布与初始孔隙压力的分布情况、在降雨入渗条件下的内部应力、有效塑性应变、塑性区、含水率、潜在滑移面等的分布情况,并计算得到滑坡体在降雨入渗条件下的安全系数。根据模型计算,滑坡体在不同降雨入渗工况下的安全系数随降雨量的增大而减小,滑坡体在连续降雨5天的临界阈值为218.82 mm,根据安全系数的变化可得到滑坡体临界降雨阈值。该论文提供了一种强度折减安全系数计算降雨型黄土滑坡降雨阈值的数值模拟方法,研究结果为西北地区降雨型黄土滑坡失稳破坏的临界降雨阈值研究提供了一种有效的研究手段。
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关键词:
- 滑坡 /
- COMSOL Multiphysics /
- 降雨阈值
Abstract: This paper takes the hidden dangerous Karahayisu Landslide in Xinyuan County, Xinjiang as a research case, and uses the COMSOL Multiphysics numerical simulation finite element software to establish a calculation model for landslide stability based on unsaturated seepage theory and Mohr-Coulomb criterion. The numerical simulation results give the original stress distribution and initial pore pressure distribution of the landslide in the study area, the internal stress, effective plastic strain, plastic zone, water content and potential slip surface distribution under rainfall infiltration conditions. The safety factor of the slope under rainfall infiltration is calculated. Based on the model calculation, the safety factor of the sliding slope decreases with the increase of rainfall under different infiltration conditions. The critical rainfall threshold of the sliding slope can be gained based on the variation of the safety factor. This study proposes a different way to calculate the rainfall threshold of rainfall-induced loess landslide using the strength reduction safety factor, also provides an effective method for studying the critical rainfall threshold of rainfall-induced loess landslide.-
Key words:
- Landslide /
- COMSOL Multiphysics /
- Rainfall threshold
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图 12 不同降雨入渗时长后坡体含水率分布图
a. 降雨入渗0 h后;b. 降雨入渗5 h后;c. 降雨入渗12 h后;d. 降雨入渗24 h后;e. 降雨入渗48 h后;f. 降雨入渗120 h后
Figure 12. Water content distribution in the slope at different infiltration time after rainfall: (a) 0 hours after rainfall infiltration; (b) 5 hours after rainfall infiltration; (c) 12 hours after rainfall infiltration; (d) 24 hours after rainfall infiltration; (e) 48 hours after rainfall infiltration; (f) 120 hours after rainfall infiltration
表 1 研究区地层岩性及分布关系表
Table 1. The table of stratigraphic lithology and distribution relationship in the study area
地层 岩性特征及分布位置 第四系上更新统风积层(Q3eol) 主要分布在监测点南部斜坡,岩性主要为粉土,厚度由坡顶向坡脚逐渐增大,总厚度小于101 m 第四系滑坡堆积层(Q4dl) 主要分布在监测点东侧沟谷内,由HP3滑坡滑动后堆积形成,岩性主要为粉土,总厚度小于10 m 第四系全新统冲洪积层(Q4apl) 主要分布在滑坡监测站北部河谷平原,地层岩性结构主要分两种,上部岩性主要以粉土为主,厚度小于30 m;下部地层多由卵砾石、沙砾等组成,厚度小于20 m 侵入岩 监测点区域内侵入岩体大多下伏于第四系以下,部分出露于南部斜坡山脊沿线,为华力西晚期第二侵入次花岗岩(γ43b),岩体多呈灰色-杂色,坚硬,矿物成分主要以斜长石、钾长石及石英为主,根据区域资料,厚度大于200m 表 2 滑坡体土层基本参数表
Table 2. Basic parameters of landslide soil layer
杨氏模量
E/Pa泊松比
μ黏聚力
c/kPa内摩擦角
φ/(°)渗透系数
Ks/m·h-1天然密度
ρ/kg·m-3孔隙比
e2.33×106 0.3 22 20 0.2 1160 0.913 表 3 模型计算工况与计算
Table 3. Model calculation conditions and calculation
序号 降雨量
/mm入渗流速
/m·h-1参数化黏聚力c′
/kPa安全系数Fr 1 56.27 0.09 18.29 1.20 2 93.78 0.15 20.00 1.10 3 125.04 0.20 20.55 1.07 4 156.30 0.25 20.83 1.06 5 187.56 0.30 21.43 1.03 6 218.82 0.35 22.74 1.00 7 250.08 0.40 22.39 0.98 -
Bai J, Ju N P, Zhang C Q, et al. 2020. Characteristics and successful early warning case of Xingyi landslide in Guizhou province[J]. Journal of Engineering Geology, 28 (6): 1246-1258. Cai Y F. 2019. Slope stability analysis and reinforcement measures under seepage-stress coupling and rainfall infiltration[D]. Hengyang: University of South China. Caine N. 1980. The rainfall intensity-duration control of shallow landslides and debris flows[J]. Geografiska Annaler A, 62(1-2): 23-27. doi: 10.1080/04353676.1980.11879996 Dong W W, Zhu H H, Sun Y J, et al. 2016. Current status and new progress of slope deformation monitoring technologies[J]. Journal of Engineering Geology, 24 (6): 1088-1095. Guzzetti F, Peruccacci S, Rossi M, et al. 2008. The rainfall intensity-duration control of shallow landslides and debris flows: an update[J]. Landslides, 5 : 3-17. doi: 10.1007/s10346-007-0112-1 Kong Y F, Song E X, Yang J, et al. 2013. Rainfall's effect on the stability of unsaturated slopes[J]. Journal of Civil, Architectural & Environmental Engineering, 35 (6): 16-21. Kong Y F, Zhou M J, Song E X, et al. 2014. Slope stability analysis in consideration of rainfall influence based on PLAXIS software[J]. Hydro-Science and Engineering, (3): 70-76. Kumar M K, Desamsetti S, Rajesh N, et al. 2020. Exploring therainfall data from satellites to monitor rainfall induced landslides-Acase study[J]. Advances in Space Research, 66 (4): 887-894. doi: 10.1016/j.asr.2020.05.015 Li F D, Li X Y, Liu W D, et al. 1993. Research progress in several fields of life science and soil science[M]. Beijing: Agricultural Press: 111-115. Li H Q, Sun H Y, Sun X M, et al. 2009. Influence of rainfall infiltration on slopes by physical model test[J]. Chinese Journal of Geotechnical Engineering, 31 (4): 589-594. Li H, Chen D L, Jia L. 2020. Numerical study on seepage stability of earth-rock dam slope based on COMSOL Multiphysics[J]. Technical Supervision in Water Resources, (3): 66-69. Li Y, Wu J, Li K. 2012. Saturated-unsaturated seepage analysis based on FLAC3D[J]. Rock and Soil Mechanics, 33 (2): 617-622. Liu C Y. 2020. Numerical simulation analysis of wind erosion instability failure process of soil slope[J]. Environmental Science and Management, 45 (3): 163-167. Liu G, Tong F G, Zhao Y T, et al. 2018. A force transfer mechanism for triggering landslides during rainfall infiltration[J]. Journal of Mountain Science, 15 : 2480-2491. doi: 10.1007/s11629-018-5043-x Meng Z J, Zhang F, Peng J B, et al. 2022. Model test research on rainfall-type loess landslide under preset joint conditions[J]. Journal of Engineering Geology, 30 (5): 1528-1537. Ma B Q, Du Y P, Wang H X, et al. 2021. Experimental study on stability of loess slope stability under continuous rainfall[J]. Journal of Soil and Water Conservation, 35(5): 50-56. Rahimi A, Rahardjo H, Leong E. 2010. Effect of antecedent rainfall patterns on rainfall-induced slope failure[J]. Journal of Geotechnical and Geoenvironmental Engineering, 137 (5): 483-491. Sun G Z, Yao B K, 1986. China landslide geological disaster and its research[C]//China Society of Rock Mechanics and Engineering Ground Rock Engineering Committee, China Geological Society Engineering Geology Committee. Typical landslide in China. Beijing: Science Press: 11. Wang G, Sun P, Wu L Z, et al. 2017. Experimental study on mechanism of shallow loess landslides induced by rainfall[J]. Journal of Engineering Geology, 25 (5): 1252-1263. Wang L L, Li N. 2021. Stability analysis of loess slope considering the effects of vertical joints[J]. Journal of Natural Disasters, 30 (6): 136-146. Wang X Q, Zhang Y X, Zou W L, et al. 2010. Numerical simulation of unsaturated road-embankment deformation and slope stability under rainfall infiltration[J]. Rock and Soil Mechanics, 31 (11): 3640-3644, 3655. Xiao J F, Li Y A, Cai J M. 2020. Model test research on response characteristics of Outang landslide under water level fluctuation[J]. Journal Engineering Geology, 28 (5): 1049-1056. Xiong Y L, Zhu H H, Ye G L, et al. 2017. Analysis of failure of unsaturated soil slope due to rainfall based on soil-water-air seepage-deformation coupling FEM[J]. Rock and Soil Mechanics, 38 (1): 284-290. Xu H, Zhu Y W, Cai Y Q, et al. 2005. Stability analysis of unsaturated soil slope under rainfall infiltration[J]. Rock and Soil Mechanics, 26 (12): 1957-1962. Xu Q. 2020. Understanding the landslide monitoring and early warning: Consideration to practical issues[J]. Journal of Engineering Geology, 28 (2): 360-374. Yang H, Hu Y J, Wu Z B. 2019. Research progress of rainfall-induced landslide prediction[J]. Science & Technology Vision, (33): 231-232. Ye S H, Shi Y L. 2018. Stability analysis of multi-stage high slope with loess under rainfall infiltration[J]. Journal of Engineering Geology, 26 (6): 1648-1656. Zhang J, Yao H Z, Wang Z P. 2021. Landslide time probability prediction method based on displacement[J]. Journal of Engineering Geology, 29 (S1): 96-105. Zhang S, Pei X J, Huang R Q, et al. 2017. Rainfall induced instability mechanism of high embankment retaining loess slope[J]. Journal of Engineering Geology, 25 (4): 1094-1104. Zheng X J, Zhu X H, Chen Y J. 2012. Stability analysis of a large landslide by strength reduction finite element method[J]. Journal of Engineering Geology, 20(S): 805-809. Zhu L F, Hu W, Jia J, et al. 2013. Development features and mechanical mechanism of irrigation-induced landslides in Heifangtai, Gansu Province[J]. Geological Bulletin of China, 32 (6): 840-846. Zienkiewicz O C, Humpheson C, Lewis R W. 1975. Associated and non-associated visco-plasticity and plasticity in soil mechanics[J]. Geotechnique, 25 (4): 671-689. doi: 10.1680/geot.1975.25.4.671 白洁, 巨能攀, 张成强, 等, 2020. 贵州兴义滑坡特征及过程预警研究[J]. 工程地质学报, 28 (6): 1246-1258. doi: 10.13544/j.cnki.jeg.2019-360 蔡亚飞. 2019. 渗流-应力耦合和降雨入渗作用下的边坡稳定性分析及加固措施[D]. 衡阳: 南华大学. 董文文, 朱鸿鹄, 孙义杰, 等. 2016. 边坡变形监测技术现状及新进展[J]. 工程地质学报, 24 (6): 1088-1095. doi: 10.13544/j.cnki.jeg.2016.06.007 孔郁斐, 宋二祥, 杨军, 等. 2013. 降雨入渗对非饱和土边坡稳定性的影响[J]. 土木建筑与环境工程, 35 (6): 16-21. https://www.cnki.com.cn/Article/CJFDTOTAL-JIAN201306003.htm 孔郁斐, 周梦佳, 宋二祥, 等. 2014. 利用PLAXIS软件计算考虑降雨的边坡稳定性[J]. 水利水运工程学报, (3): 70-76. https://www.cnki.com.cn/Article/CJFDTOTAL-SLSY201403011.htm 李阜棣, 李学垣, 刘武定, 等. 1993. 生命科学和土壤学中几个领域的研究进展[M]. 北京: 农业出版社: 111-115. 李焕强, 孙红月, 孙新民, 等. 2009. 降雨入渗对边坡性状影响的模型实验研究[J]. 岩土工程学报, 31 (4): 589-594. https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC200904020.htm 李辉, 陈大雷, 贾璐. 2020. 基于COMSOL Multiphysics的土石坝边坡渗流稳定数值研究[J]. 水利技术监督, (3): 66-69. https://www.cnki.com.cn/Article/CJFDTOTAL-SLJD202003020.htm 李毅, 伍嘉, 李坤. 2012. 基于FLAC3D的饱和-非饱和渗流分析[J]. 岩土力学, 33 (2): 617-622. https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX201202049.htm 刘聪裕. 2020. 土质边坡风蚀失稳破坏过程数值模拟分析研究[J]. 环境科学与管理, 45 (3): 163-167. https://www.cnki.com.cn/Article/CJFDTOTAL-BFHJ202003034.htm 孟振江, 张凡, 彭建兵, 等. 2022. 预设节理条件下降雨型黄土滑坡模型试验研究[J]. 工程地质学报, 30 (5): 1528-1537. doi: 10.13544/j.cnki.jeg.2022-0434 马蓓青, 杜玉鹏, 王怀星, 等. 2021. 持续降雨条件下黄土边坡稳定性试验研究[J]. 水土保持学报, 35(5): 50-56. https://www.cnki.com.cn/Article/CJFDTOTAL-TRQS202105008.htm 孙广忠, 姚宝魁. 1986. 中国滑坡地质灾害及其研究[C]//中国岩石力学与工程学会地面岩石工程专业委员会, 中国地质学会工程地质专业委员会. 中国典型滑坡. 北京: 科学出版社: 11. 王刚, 孙萍, 吴礼舟, 等. 2017. 降雨诱发浅表层黄土滑坡机理实验研究[J]. 工程地质学报, 25 (5): 1252-1263. doi: 10.13544/j.cnki.jeg.2017.05.010 王丽丽, 李宁. 2021. 垂直节理对黄土边坡稳定性影响分析[J]. 自然灾害学报, 30 (6): 136-146. https://www.cnki.com.cn/Article/CJFDTOTAL-ZRZH202106015.htm 王协群, 张有祥, 邹维列, 等. 2010. 降雨入渗条件下非饱和路堤变形与边坡的稳定数值模拟[J]. 岩土力学, 31 (11): 3640-3644, 3655. https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX201011047.htm 肖捷夫, 李云安, 蔡浚明. 2020. 水位涨落作用下藕塘滑坡响应特征模型试验研究[J]. 工程地质学报, 28 (5): 1049-1056. doi: 10.13544/j.cnki.jeg.2020-326 熊勇林, 朱合华, 叶冠林, 等. 2017. 降雨入渗引起非饱和土边坡破坏的水-土-气三相渗流-变形耦合有限元分析[J]. 岩土力学, 38 (1): 284-290. https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX201701038.htm 徐晗, 朱以文, 蔡元奇, 等. 2005. 降雨入渗条件下非饱和土边坡稳定分析[J]. 岩土力学, 26 (12): 1957-1962. https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX200512020.htm 许强. 2020. 对滑坡监测预警相关问题的认识与思考[J]. 工程地质学报, 28 (2): 360-374. doi: 10.13544/j.cnki.jeg.2020-025 杨欢, 胡云进, 吴振波. 2019. 降雨型滑坡预测预报研究进展[J]. 科技视界, (33): 231-232. https://www.cnki.com.cn/Article/CJFDTOTAL-KJSJ201933115.htm 叶帅华, 时轶磊. 2018. 降雨入渗条件下多级黄土高边坡稳定性分析[J]. 工程地质学报, 26 (6): 1648-1656. doi: 10.13544/j.cnki.jeg.2017-552 张洁, 姚鸿增, 王梓芃. 2021. 基于位移的滑坡时间概率预测方法[J]. 工程地质学报, 29 (S1): 96-105. doi: 10.13544/j.cnki.jeg.2021-0353 张硕, 裴向军, 黄润秋, 等. 2017. 降雨诱发黄土高填方支挡边坡失稳机理研究[J]. 工程地质学报, 25 (4): 1094-1104. doi: 10.13544/j.cnki.jeg.2017.04.024 郑孝军, 朱雪蕻, 陈亚军. 2012. 某大型滑坡强度折减法有限元稳定性分析[J]. 工程地质学报, 20(S): 805-809. https://cpfd.cnki.com.cn/Article/CPFDTOTAL-GCDZ201210001144.htm 朱立峰, 胡炜, 贾俊, 等. 2013. 甘肃永靖黑方台地区灌溉诱发型滑坡发育特征及力学机制[J]. 地质通报, 32 (6): 840-846. https://www.cnki.com.cn/Article/CJFDTOTAL-ZQYD201306003.htm -