汶川县震后公路泥石流风险分析
文献类型：学位论文
| 作者 | 向灵芝 |
| 学位类别 | 博士 |
| 答辩日期 | 2012-05-20 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 崔鹏 |
| 关键词 | 汶川大地震 泥石流活动特征 公路 地貌演化 风险分析 |
| 其他题名 | The Risk Assessment of Debris Flow along Highway after the Earthquake in Wenchuan Couty |
| 学位专业 | 自然地理学 |
| 中文摘要 | 论文选择汶川地震极震区汶川县为研究区，开展公路泥石流风险分析，主要研究成果如下： 1、对汶川县公路沿线地震崩塌、滑坡开展了系统的考察，查明了都汶公路和省道303两侧的崩塌滑坡松散堆积物质的分布特征，为震后泥石流活动特征与风险分析提供基础数据。 2、对汶川县震后公路泥石流灾害做了系统的调查，归纳出汶川县主要公路沿线泥石流震后活动特征主要体现在以下4个方面：1）泥石流流体性质以粘性为主；2）暴发规模明显增大，沟道堵塞严重；3）泥石流多发生在面积较小的流域；4）高频性与群发性特点显著。震后泥石流对公路的危害较震前明显加剧，以高强度淤积和频繁堵江为特点，其危害方式分为直接危害和间接危害，直接危害包括：1）泥石流对公路桥涵的堵塞、冲击，2）泥石流对公路路面或桥涵的淤积和淤埋；间接危害包括：1）泥石流冲入河流后形成壅塞体，使河床淤积抬高，使河流中轴线发生变化，形成曲流，对桥墩、路基等形成强烈冲刷，2）泥石流堵塞河流，河水上涨，淹没公路。 3、基于地貌演化理论，结合蒋家沟流域研究成果，提出研究区主要公路沿线两侧泥石流沟敏感性初判分析方法。从震后泥石流发生的机理出发，选取流域面积、主沟比降、固体物质参照值、降雨等11个因子作为评价指标，利用灾害熵模型确定出灾害发生的关键因素并进行震后泥石流敏感性评价，其分析结果与震后的泥石流灾害实际情况较为一致。基于两种方法泥石流敏感性的对比分析表明，研究区泥石流流域大部分属于地貌演化的壮年阶段，且在震后受地质地貌基础的不稳定性以及地震诱发崩塌滑坡物质量的分布和高强度降雨的影响，属于较高敏感性泥石流沟由占总数的65%增加至78.3%。 4、依据单沟泥石流成灾过程，考虑泥石流对公路的危害方式，选取泥石流规模、泥石流淤埋公路程度、泥石流堵江程度3个因子作为泥石流对沿河公路危险性评价的指标，提出了这些指标的定量确定方法，建立基于泥石流成灾过程的危险性评估方法。根据公路的承灾特点和公路构筑物的抗灾能力，选取经济价值和防灾能力两类因子作为沿河公路的易损性评价指标，针对路基和桥涵分别确定具体评价因子并分级量化，建立了易损性评价方法。在此基础上结合GIS技术，提出了泥石流危害公路的风险评价和风险制图方法。运用上述方法对S303线全线和典型灾点进行石流危害公路风险评价，结果与实际调查灾情较为一致。此方法可以用于震后山区公路泥石流风险分析。 |
| 英文摘要 | This paper chose Wenchuan County ,the epicenter of Wenchuan earthquake as research area.Risk assessment of debris flow along Highway is carried out The main achievement can be concluded as following: 1、The systematic investigation of collapses and landslides induced by earthquake in Wenchuan County is carried out to identify the distribution characteristics of a loose substances for the debris flow along the highway after the earthquake,and provide the basic data for the debris flow activity features and risk analysis 2、The activity characteristics of debris flow had remarkable changes after the Wenchuan Earthquake and the main changes were as follows: 1）the fluid dominated by viscous, 2）serious channel blockage caused large-scale debris flows, 3）mainly occurred in smaller basin, 4）characterized by high frequency and group-occurring, and the damage caused by debris flow along highway can be classified into direct damage and indirect damage, including blocking, scouring, burying and submerging. The direct damage includes: 1) road and bridge being blocked and impacted, 2) road pavements and tunnels being deposited and buried. Indirect damage includes: 1) the main river bed being raised by debris flow deposit, and the piers and subgrade being scoured strongly by branch flow, 2) the main river being blocked by debris flow, and forming dammed lakes which submerge the road. 3、Based on the geomorphic evolution theory and the Jiangjia ravine research，the sensitivity analysis methods of debris flow gullies along the Du-Wen Highway and Provincial Highway 303 are proposed. The watershed area , the main ditch slope, the solid material reference value and other 11 factors are selected as the evaluation index based on the mechanism of the debris flow after the earthquake. Then the disaster entropy model is used to determine the key factors of disasters and debris flow sensitivity evaluation after the earthquake. The analysis is more consistent with the actual disaster. The comparative analysis of the debris flow sensitive based on these two methods shows that, Most of the debris flow basin of the study area belongs to the prime of life stages of the geomorphic evolution.Affecting by instability of geological eviroment, the distribution of earthquake-induced landslide material and high-intensity rainfall after the earthquake, the higher sensitivity of debris flow gullies by accounting for 65% of the total increased to 78.3%. 4、In order to explore effective risk methods to objectively evaluate the debris-flow hazards along highways, three key indexes including the scale of debris flow, highway depositing degree and river blocking degree are chosen to determine the hazard of debris flow through combining with the hazard effect modes and disaster process in a single debris flow. And then, a quantitative method to determine the hazard indexes is proposed. In addition, the economic value and anti-disaster capability are used as vulnerability assessment indexes of highway; and specific evaluation indexes for the subgrade, bridges and culverts are determined respectively. Then quantified vulnerability zoning has been realized. Moreover, a risk assessment method and a methodology of risk mapping for debris flows along highways are demonstrated. Furthermore, a case study was carried out on provincial highway S303 from Yingxiu Town to Wolong Town in Wenchuan County. Applying this method in analysis of debris flows along the whole highway, the risk assessment result is consistent with the actual disaster situation.The quantitative analysis method established in this paper is suitable for risk assessment of roads along rivers in mountainous areas, which also has reference value for road reconstruction and mitigation in seismic areas. |
| 语种 | 中文 |
| 公开日期 | 2013-01-16 |
| 源URL | [http://192.168.143.20:8080/handle/131551/4817]  |
| 专题 | 成都山地灾害与环境研究所_山地灾害与地表过程重点实验室 |
| 推荐引用方式 GB/T 7714 | 向灵芝. 汶川县震后公路泥石流风险分析[D]. 北京. 中国科学院研究生院. 2012. |
入库方式： OAI收割
来源：成都山地灾害与环境研究所
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