巴谢河流域滑坡易发性评价

发布时间：2018-02-02 15:27

本文关键词： 巴谢河流域滑坡易发性评价　出处：《兰州大学》2017年硕士论文　论文类型：学位论文

【摘要】：巴谢河流域作为黄土高原陇西地区临夏盆地滑坡密集发育的典型区,区内滑坡分布广泛、活动频繁,威胁着当地人民的生命财产安全。为有效地制定区域滑坡灾害宏观防治政策,就需要从区域上对滑坡灾害进行易发性区划,GIS的运用极大地提高了滑坡易发性评价的工作效率。基于遥感解译与野外调查,查明了巴谢河流域滑坡的位置、数量、分布及规模等,总结了流域内滑坡的类型及分布特征。通过遥感、地形与地质等多源数据集成,实现滑坡影响因素的提取,选用斜坡单元作为评价单元,定量地分析了滑坡与其影响因素间的关系。从全区249处滑坡中随机选择70%的样本数据用于构建EBF、频率比及确定性系数3种评估模型,而剩下30%的滑坡点用于模型的验证,绘制出滑坡易发性分区图。同时利用成功率曲线与预测率曲线对评价结果进行精度检验,探讨了模型的可信程度。获得的主要研究成果如下:(1)流域内滑坡规模以大、中型为主,厚度以中、深层居多,沿河流沟谷线性展布;河流两岸滑坡呈不对称发育,且在其两岸沟口处多发育大型滑坡;在黄土厚度大的中、下游地段多分布有大型、深层滑坡;同时显现出同一地点复活性较强的特性;滑坡在时间上具有多期性,后期发生的滑坡常改造前期形成的滑坡。(2)滑坡分布与地形地貌关系密切,高程2000~2200m、坡度15°~30°、起伏度100~200m、阳坡坡向、切割深度50~100m及沟谷密度1~2.5km/km2的范围内,滑坡尤为发育;滑坡与地层岩性、植被、人类活动等有较好的对应关系,其中岩性为马兰黄土及泥岩、NDVI在0.2~0.3与距离道路600m的范围内滑坡易于发生。(3)把区内滑坡易发性程度分为5个级别:极低易发、低易发、中易发、高易发、极高易发。通过计算得到,EBF模型、CF模型、FR模型成功率曲线下方面积分别为0.8038、0.7924、0.8088,预测率曲线下方面积分别为0.8056、0.7922、0.7989。可以看出,3种模型得到的滑坡易发性区划图对滑坡空间分布的反映与预测较为相似,曲线下方的面积都很接近,但综合考量成功率与预测率来看,EBF模型的评价结果要略优于FR模型、CF模型。
[Abstract]:As a typical area of intensive development of landslides in the Linxia basin of Longxi region of the Loess Plateau, the Basie River Basin has a wide distribution of landslides and frequent activities. It threatens the safety of local people's life and property. In order to effectively formulate the macro-control policy of regional landslide disaster, it is necessary to regionalize the vulnerability of landslide disaster. The application of GIS has greatly improved the work efficiency of landslide vulnerability evaluation. Based on remote sensing interpretation and field investigation, the location, quantity, distribution and scale of landslide in Basei River Basin have been found out. The types and distribution characteristics of landslide in the basin are summarized. Through the integration of multi-source data such as remote sensing, topography and geology, the extraction of landslide influencing factors is realized, and the slope unit is selected as the evaluation unit. The relationship between landslide and its influencing factors was analyzed quantitatively. 70% samples were randomly selected from 249 landslides in the whole area to construct three evaluation models of EBF, frequency ratio and deterministic coefficient. The remaining 30% landslide points are used to verify the model and draw the landslide susceptibility zoning map. At the same time, the accuracy of the evaluation results is verified by using the success rate curve and the prediction rate curve. The main results obtained are as follows: the scale of landslide in the basin is large and medium, the thickness is medium and deep, and the distribution is linear along the river valley; The landslide on both sides of the river develops asymmetrically, and large landslide is developed at the gully of the river. In the middle and lower reaches of loess, there are large and deep landslides. At the same time, it showed the characteristics of strong resurrection in the same place. Landslide has multi-period character in time. The landslide distribution formed in the early stage of landslide reconstruction is closely related to landform and landform. The elevation is 2000 ~ 2200mand the slope is 15 掳~ 30 掳. The landslide is especially developed in the range of 100 ~ 200m of fluctuation, 50 ~ 100m of cutting depth and 1 ~ 2.5km / km ~ 2 of valley density. Landslide has a good relationship with stratigraphic lithology, vegetation, human activities and so on, among which the lithology is Ma Lan loess and mudstone. NDVI is within the range of 0.2m and 600m away from the road.) the susceptibility of landslide in this area is divided into five grades: very low, low, moderate and high. The area under the success rate curve of CF / FR model is 0.8038 / 0.7924 / 0.8088, respectively. The area under the forecast rate curve is 0.8056U 0.7922g 0.79899.It can be seen. The spatial distribution of landslide obtained from the three models is similar to that of prediction, and the area below the curve is very similar, but considering the success rate and prediction rate. The evaluation results of EBF model are slightly better than that of FR model / CF model.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P642.22

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