Hazard Assessment of Typical Debris Flow Induced by Rainfall Intensity
-
摘要: “5·12”汶川地震后大量滑坡崩塌体出现,伴随极端降雨极易向泥石流转换,其规模及危害程度远高于预期.2010年8月13日都江堰龙池场镇突发暴雨,导致八一沟泥石流暴发,冲毁拦挡坝,掩埋道路、房屋及农田.为了探索降雨驱动泥石流的危险性,选取八一沟泥石流作为研究对象,通过分析不同降雨频率下的泥石流暴发强度及周期,采用FLO-2D数值模拟方法开展危险性评价.经验证模拟精度可达78%,结合降雨频率(5年、20年、50年、100年、200年)、流速和堆积深度构建八一沟泥石流危险性评价模型并绘制分布图.结果表明,八一沟泥石流危险范围内高危险区占62%,中危险性区占28%,低危险区占10%,该结论为危险范围内重点设施的监测预警提供科学依据.Abstract: A large number of landslides and rock falls were produced in the meizoseismal area by the "5·12" Wenchuan earthquake. If an extreme rainfall occurred, lots of materials could be transformed into debris flow, with larger size and higher damage degree than expected. On 13th October 2010, debris flow occurred in Bayi gully in Dujiangyan County under rainstorm condition, destroying dam, burying road, houses and farms, and seriously affecting the daily life of local people. In order to reduce these damage, Bayi gully was selected as the research object. Combined debris flow intensity under the different rainfall frequency and period of the outbreak, this paper aims to obtain Bayi gully hazard assessment by the FLO-2D numerical simulation. First, the Bayi gully numerical simulation accuracy can reach 77% according to field test. Then, according to the different frequency of rainfall (5 years, 20 years, 50 years, 100 years, 200 years) and the debris flow velocity and deposit depth, the hazard assessment model is established. Finally, the hazard map of Bayi gully is obtained. The results show that the high hazard area accounted for 62% in the Bayi gully, the medium hazard area accounted for 28%, and the low hazard area accounted for 10%. The hazard assessment of Bayi gully can provide a reliable basis for the post-disaster reconstruction and the key area prevention.
-
Key words:
- Bayi gully mud flow /
- FLO-2D /
- rainfall frequency /
- hazard assessment /
- engineering geology /
-
表 1 八一沟泥石流③号集水点20年一遇参数选取
Table 1. The parameter of ③ set point in Bayi basin under 20 years rainfall frequency
参数 数值 流域面积F(km2) 2.08 沟道长度L(km) 2.5 径流系数ψ 0.918 洪峰流量QP(m3/s) 37.46 洪水流量WP(104m3) 5.62 体积浓度CV 0.6 径流深度H(cm) 27 汇流时间τ(h) 1.2 曼宁系数 0.05 屈服强度τy(MPA) 4 903 粘滞系数η 5 704 放大系数BF 2.5 表 2 八一沟泥石流数值模拟精度表
Table 2. Accuracy of numerical simulation in Bayi gully
泥石流名称 “8·13”泥石流堆积面积 实测值(103 m2) 模拟值(103 m2) 重叠区(103 m2) 精确程度 八一沟泥石流 136.48 112.28 109.09 0.78 表 3 八一沟泥石流强度划分表
Table 3. Debris flow intensity partition in Bayi gully
八一沟泥石流强度 堆积深度(m) 关系式 堆积深度与流速乘积(m2/s) 高 H≥2.5 OR VH≥2.5 中 0.5≤H<2.5 AND 0.5≤VH<2.5 低 0.0≤H<0.5 AND VH<0.5 -
Chang, M., Tang, C., Zhang, D.D., et al., 2014. Debris Flow Susceptibility Assessment Using a Probabilistic Approach: a Case Study in the Longchi Area, Sichuan Province, China. Journal of Mountain Science, 11(4): 1001-1014. https://doi.org/10.1007/s11629-013-2747-9 Chang, M., Tang, C., 2014. Study on Typical Movement Model in Mine Debris Flow Based on Hydrodynamic Force Conditions. Journal of Hydraulic Engineering, 33:116-121(in Chinese with English abstract). http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=slxb201411007 Christen, M., Kowalski, J., Bartelt, P., et al., 2010. RAMMS: Numerical Simulation of Dense Snow Avalanches in Three-Dimensional Terrain. Cold Regions Science and Technology, 63: 1-14. https://doi.org/10.1016/j.coldregions.2010.04.005 Cui, P., Zou, Q., 2016. Theory and Method of Risk Assessment and Risk Management of Debris Flows and Flash Floods. Progress in Geography, 35(2):137-147(in Chinese with English abstract). doi: 10.18306/dlkxjz.2016.02.001 Dai, F.C., Lee, C.F., Ngai, Y.Y., et al., 2012. Landslide Risk Assessment and Management an Overview. Engineering Geology, 64:65-87. https://doi.org/10.1016/S0013-7952(01)00093-X Du, J., Yang, Q.H., Yan, J., et al., 2010. Hazard Evaluation of Secondary Geological Disaster Based on GIS and Information Value Method. Earth Science, 35(2):324-330(in Chinese with English abstract). http://d.old.wanfangdata.com.cn/Periodical/dqkx201002018 Huang, Y., Cheng, H.L., Dai, Z.L., et al., 2015. SPH-Based Numerical Simulation of Catastrophic Debris Flows after the 2008 Wenchuan Earthquake. Bulletin of Engineering Geology and the Environment, 74:1137-1151. https://doi.org/10.1007/s10064-014-0705-6 Liu, X.L., Shang, Z.H., 2012. Integrated Risk Analysis Methodology of Debris Flow Disaster and the Study Case. Geography and Geo-Information Science, 28(5):86-89(in Chinese with English abstract). http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=dlxygtyj201205019 Ma, Y., Yu, B., Wu, Y.F., et al., 2011. Research on the Disaster of Debris Flow of Bayi Gully, Longchi, Dujiangyan, Sichuan on August 13, 2010. Journal of Sichuan University (Engineering Science Edition), 43(1):92-98(in Chinese with English abstract). http://cn.bing.com/academic/profile?id=dda1fe1941a33d48a80190ca6dddb3bf&encoded=0&v=paper_preview&mkt=zh-cn Mamodu, A., Dinand, A., 2013. Post Seismic Debris Flow Modelling Using FLO-2D; Case Study of Yingxiu, Sichuan Province, China. Journal of Geography and Geology, 5(3): 101-115. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=Doaj000002747885 Nocentini, M., Tofani, V., Gigli, G., et al., et al., 2015. Modeling Debris Flows in Volcanic Terrains for Hazard Mapping: the Case Study of Ischia Island (Italy). Landslides, 12(5):831-846. https://doi.org/10.1007/s10346-014-0524-7 Peng, S.X., Lu, S.C., 2012. FLO-2D Simulation of Mudflow Caused by Large Landslide Due to Extremely Heavy Rainfall in Southeastern Taiwan during Typhoon Morakot. Journal of Mountain Science, 10(2): 207-218. https://doi.org/10.1007/s11629-013-2510-2 Qin, Y., Zhang, H.C., 2013. Initiation Conditions for the 8·13 Debris Flows in Bayi Gully of Dujiangyan. South-to-North Water Transfers and Water Science & Technology, 11(4):101-104(in Chinese with English abstract). http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=nsbdyslkj201304023 Quan, L. B., Blahut, J., Van Westen, C.J., et al., 2011. The Application of Numerical Debris Flow Modelling for the Generation of Physical Vulnerability Curves. Natural Hazards and Earth System Sciences, 11: 2047-2060. doi: 10.5194/nhess-11-2047-2011 Quan, L. B., Cepeda, J., Stumpf, A., et al., 2013. Analysis and Uncertainty Quantification of Dynamic Run-Out Model Parameters for Landslides. In: Margottini, C., Canuti, P., Sassa, K., eds., Landslide Science and Practice. Springer, Berlin, Heidelberg, 315-318. Shen, J.H., Zhu, R.C., Liu, W.G., et al., 2008. Possibility Geological Analysis of Gangou Debris Flow in Longchi Town in Dujiangyan Induced by the Earthquake of May 12 in Wenchuan. Mountain Science, 26(5):513-517(in Chinese with English abstract). http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=sdxb200805001 Tang, C., Li, W.L., Ding, J., et al., 2011. Field Investigation and Research on Giant Debris Flow on August 14, 2010 in Yingxiu Town, Epicenter of Wenchuan Earthquake. Earth Science, 36(1):172-180(in Chinese with English abstract). http://d.old.wanfangdata.com.cn/Periodical/dqkx201101018 Tang, C., Qi, X., Ding, J., et al., 2010. Dynamic Analysis on Rainfall-Induced Landslide Activity in High Seismic Intensity Areas of the Wenchuan Earthquake Using Remote Sensing Image. Earth Science, 35(2):317-323(in Chinese with English abstract). http://d.old.wanfangdata.com.cn/Periodical/dqkx201002017 Tang, C., Van Asch., T.W.J., Chang, M., et al., 2011. Catastrophic Debris Flows on 13 August 2010 in the Qingping Area, Southwestern China: The Combined Effects of a Strong Earthquake and Subsequent Rainstorms. Geomorphology, 139: 559-576. https://doi.org/10.1016/j.geomorph.2011.12.021 Zhan, Q.D., Xiao, K.W., Xu, Y.C., 2015. Applying FLO-2D and Debris 2D Model to Simulate Characteristics of Debris Flow in Qianghuangkeng Watershed. Journal of the Taiwan Disaster Prevention Society, 7(2):239-247(in Chinese with English abstract). Zhang, Z.G., Zhang, Z.M., Zhang, S.B., et al., 2010. Formation Conditions and Dynamics Features of the Debris Flow in Bayi Gully in Dujiangyan County. The Chinese Journal of Geological Hazard and Control, 21(1):34-38(in Chinese with English abstract). http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=zgdzzhyfzxb201001007 Zhou, W., Chen, N.S., Deng, M.F., et al., 2011. Dynamic Characteristics and Hazard Risk Assessment of Debris Flows in Bayi Gully of Dujiangyan City of Sichuan Province. Bulletin of Soil and Water Conservation, 31(5):138-143(in Chinese with English abstract). http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=stbctb201105027 Zhou, W., Tang, C., 2014. Rainfall Thresholds for Debris Flow Initiation in the Wenchuan Earthquake-Stricken Area, Southwestern China. Landslides, 11(5):877-887. https://doi.org/10.1007/s10346-013-0421-5 常鸣, 唐川, 2014.基于水动力的典型矿山泥石流运动模式研究.水利学报, 33:116-121. http://d.old.wanfangdata.com.cn/Periodical/slxb201411007 崔鹏, 邹强, 2016.山洪泥石流风险评估与风险管理理论与方法.地理科学进展, 35(2):137-147. http://d.old.wanfangdata.com.cn/Periodical/dlkxjz201602001 杜军, 杨青华, 严嘉, 等, 2010.基于GIS与信息量模型的汶川次生地质灾害危险性评价.地球科学, 35(2):324-330. http://earth-science.net/WebPage/Article.aspx?id=1958 刘希林, 尚志海, 2012.泥石流灾害综合风险分析方法及其应用.地理与地理信息科学, 28(5):86-89. http://d.old.wanfangdata.com.cn/Periodical/dlxygtyj201205019 马煜, 余斌, 吴雨夫, 等, 2011.四川都江堰龙池"8·13"八一沟大型泥石流灾害研究.四川大学学报(工程科学版), 43(1):92-98. http://www.cqvip.com/QK/90462B/2011S1/1003577949.html 沈军辉, 朱容辰, 刘维国, 等, 2008. "5·12"汶川地震诱发都江堰龙池镇干沟泥石流可能性地质分析.山地学报, 26, (5):513-517. doi: 10.3969/j.issn.1008-2786.2008.05.001 覃怡, 郑洪春, 2013.都江堰八一沟8·13泥石流的形成条件分析.南水北调与水利科技, 11(4):101-104. http://d.old.wanfangdata.com.cn/Periodical/nsbdyslkj201304023 唐川, 李为乐, 丁军, 等, 2011.汶川震区映秀镇"8.14"特大泥石流灾害调查.地球科学, 36(1):172-180. http://earth-science.net/WebPage/Article.aspx?id=2076 唐川, 齐信, 丁军, 等, 2010.汶川地震高烈度区暴雨滑坡活动的遥感动态分析.地球科学(, 35(2):317-323. http://earth-science.net/WebPage/Article.aspx?id=1957 詹钱登, 萧凯文, 徐郁超, 等, 2015.应用FLO-2D及Debris 2D模拟羌黄坑集水区内土石流流动特性差异之研究.中华防灾学刊, 7(2):239-247. 张自光, 张志明, 张顺斌, 等, 2010.都江堰市八一沟泥石流形成条件与动力学特征分析.中国地质灾害与防治学报, 21(1):34-38. doi: 10.3969/j.issn.1003-8035.2010.01.007 周伟, 陈宁生, 邓明枫, 等, 2011.四川省都江堰市八一沟泥石流动力学特征及危险性评估.水土保持通报, 31(5):138-143. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=stbctb201105027