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以2003年3月的1/5万航片为主要遥感信息源,1/1万地形图为地理控制信息源;采用“数字滑坡”技术方法在三峡水库区中前段8个城镇调查区获取了投影面积大于1000m2的826个滑坡的分布及其发育环境的基本信息。分析表明各调查区滑坡分布的平均地面密度有较大差异。其中大坝-秭归调查区最低,约1.6‰,巴东、奉节区滑坡分布地面密度最大,分别达到8.0%、7.6%;各区滑坡均有明显的集中密集分布特点。巫山县北岸为调查区滑坡分布线密度最大的岸坡;滑坡堆积的后前缘在海拔970~65m范围,区域滑坡分布最高高程与该区的地势相应,前缘最低高程与该处最低侵蚀基准面相当。本区80%以上的滑坡分布在海拔400~100m——人类活动最强烈的高程范围。滑坡分布特征揭示地层是控制三峡水库区中前段滑坡发育的最重要的地质环境因素。提出“易滑指数—ES”和“区域易滑指数—RES”概念,以此说明区内各地层易于发育滑坡的程度及其分布比例。三叠系中统巴东组T2b和侏罗系沙溪庙组J2s为调查区分布最广、发育滑坡最多、滑坡平均规模最大的易滑地层。构造对滑坡分布的控制作用表现在当褶皱构造走向与江河走向一致时,滑坡大部发育在顺层坡,特别是近轴部位置;当褶皱与江河斜交时,其对滑坡分布的控制作用不明显。滑坡前缘分布持征表明江河侵蚀是诱发本区滑坡的重要因素。三峡水库蓄水后侵蚀条件改变,滑坡活动将增加,其大部分由人类不合理活动诱发。
One hundred and five thousand aerial photos were taken as the main remote sensing information source in March 2003 and 1/10 ten topographic maps were used as geographic control information sources. The digital landslide technique was used in the survey areas of 8 towns in the front section of the Three Gorges Reservoir The distribution of 826 landslides with projected area greater than 1000m2 and the basic information of their developmental environment. The analysis shows that the average surface density of landslide distribution in each survey area is quite different. Among them, the dam-Zigui surveyed area is the lowest, about 1.6 ‰. The landslide distributions in Badong and Fengjie are the highest, with 8.0% and 7.6% respectively. The landslides in all areas have obvious concentrated dense distribution. The north bank of Wushan County is the bank slope with the highest density of landslides in the survey area. The posterior leading edge of the landslide accumulates in the range of 970-65m above sea level. The highest elevation of regional landslides corresponds to the topography of the area. The lowest elevation of the frontal edge and the lowest erosion standard Quite equivalent. More than 80% of landslides in this area are distributed in the altitude of 400 ~ 100m - the most intense elevation of human activities. The distribution of landslides reveals that the strata are the most important geo-environmental factors controlling the landslide development in the middle section of the Three Gorges Reservoir. The concept of “slippery index-ES” and “regional slip index-RES” are put forward to illustrate the degree and proportion of landslide prone to various strata in the area. Triassic Zhongbadongdong group T2b and Jurassic Shaximian formation J2s are the most widely distributed, developed landslides and landslides with the largest average slippery strata. The controlling effect of tectonics on the landslide distribution is that when the trend of fold structure is consistent with that of the river, most of the landslide develops in the bedding slope, especially near the axis. When the folds and the river are inclined, the controlling effect on the landslide distribution Not obvious. Landslide front distribution shows that river erosion is an important factor in causing the landslide in this area. After the Three Gorges Reservoir water erosion conditions change, landslide activity will increase, the majority of human induced by unreasonable activities.