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综合采用现场调查、测量及室内理论分析等方法,以金沙江干流寨子村巨型滑坡群和金沙江支流海口大型滑坡为例,对滑坡堵江的地貌效应进行了初步探讨。寨子村古滑坡群的滑坡坝及堰塞湖沉积均有残留,后者沿江分布长度55km,面积约120km~2。堵江段的金沙江平面弯曲、纵断面比降小、横断面宽而浅,具有平原区河流特征,与非堵江段差异显著。堰塞湖沉积分布区地形开阔,发育有土塬、冲沟及土梁等地貌单元,有时还会发生沙尘暴。海口滑坡的滑坡坝和堰塞湖沉积均保存完整:前者顺河水平投影长约1000m、最大厚度135m,后者沿河长3km、面积8km~2;两者分别使海口河河床比降增大、减小了11‰和95‰。滑坡堵江的地貌效应显著,它可以抑制高山峡谷区的河流底蚀,使之成为“走两步退一步”的自我调节过程,而营造开阔空间的堰塞湖沉积大多都可开垦为农田,在长期影响所在区域地貌演化的同时,也为人类在复杂山区创造了若干宜居场所。
Taking the large landslide group of Zhaizi village in the mainstream of Jinshajiang River and Haikou large-scale tributary of Jinsha River as an example, the paper first discussed the landform effect of landslide plugging by comprehensively adopting the methods of on-the-spot investigation, measurement and indoor theoretical analysis. The landslide dams and dammed lakes of the Zhaiziqu Ancient Landslide Group are all left with a length of 55km and an area of 120km ~ 2 along the river. The Jinsha River in the section of Jiangdu section is curved, the vertical section ratio is reduced, the section is wide and shallow, and has the characteristics of rivers in the plain area. Dammed lake sedimentary distribution of open terrain, the development of a plateau, gully and earth beams and other geomorphological units, and sometimes sandstorms. The landslide dam and dammed lake sediments of Haikou landslide are all preserved intact: the former transversal horizontal projection is about 1000m long and the maximum thickness is 135m, the latter is 3km long and the area is 8km ~ 2; , A decrease of 11 ‰ and 95 ‰. Landslide blocking the river has obvious landform effect, which can restrain the river bottom erosion in alpine gorge area, making it a self-regulating process of “taking two steps backwards” and most of the dammed lake deposits that create open space can be reclaimed as Farmland, while permanently affecting the geomorphological evolution in the region, has also created a number of livable places for human beings in complex mountainous areas.