摘要
我国每年约有30%地质灾害发生在约占国土面积6%黄土高原地区,灾害数量多、危害严重、机理复杂,然而由于对黄土灾害的发生规律仍然不明晰,长期以来制约了区内大型工程建设、移民搬迁选址等工作.依托1:5万黄土高原区地质灾害调查数据,通过专题要素图件编制和数理统计等手段,重点分析11680处地质灾害,总结了灾害时空分布规律.结果表明,1)在区域地质构造抬升的背景下,黄土高原地形破碎,地貌沟壑纵横,具有滑坡、崩塌、泥石流等地质灾害多发的特点.2)地质灾害具有明显的时空发生规律,在整个黄土高原区域尺度上,地貌演化与斜坡结构控制地质灾害空间分布和斜坡破坏模式;在流域尺度上,老年期、壮年期、幼年期等沟谷发育期控制着地质灾害变形破坏模式及危害程度;在具体斜坡点上,坡型、坡度、坡高等坡体几何形态控制地质灾害的类型和失稳概率;在时间上,降雨及冻融作用控制年内地质灾害的分布.
There are about 30%of the total geological hazards occurring on the Loess plateau of China each year,but they occupy only about 6%of Chinese land area.Although loess geohazard are characterized by diverse types and large occurrences,complicated mechanisms and serious aftermaths,their occurrence regularity are still unclear,which has restricted the construction of large-scale projects,relocation and site selection of immigrants in the region for a long time.In this study,it inspected the catalog data from a report of geohazard survey with the scale of 1:50000 in the Loess Plateau area,campaigned by China Geological Survey since 2005.11680 geological disaster records were scrutinized with reexamination of detailed information.The temporal and spatial distribution of loess geohazards was delineated by statistics analysis and compilations of thematic maps of geohazard survey.The results show that:1)under the influence of regional tectonic uplift,vertical and horizontal gullies richly developed in broken loess terrain contributed to frequent occurrences of loess geohazard such as landslide,collapse and debris flow.2)Loess geohazards are characterized by obvious spatio-temporal formation.As viewed from a regional scale of the Loess Plateau,geomorphological evolution and slope structure of loess massif dominated the spatial distribution of loess geohazards and slope failure modes;On the basin scale,the deformation and failure modes of loess slopes,as well as the resulting aftermaths were associated with the evolution phases of loess gullies,such as old-stage,adult-stage and young-stage of a gully;At a given slope site,the morphology of a slope such as geometry,inclination,height,etc.determined the type of loess geohazards and their failure probability;As viewed from time scale,loess geohazards mostly occurred during monsoon,freezing-thawing seasons in a year.This research would provide a scientific insight into loess geohazard regularity in different circumstances.
作者
孙萍萍
张茂省
程秀娟
黄玉华
薛强
刘洁
SUN Pingping;ZHANG Maosheng;CHENG Xiujuan;HUANG Yuhua;XUE Qiang;LIU Jie(State Key Laboratory of Continental Dynamics,Department of Geology,Northwest University,Xian 710069,China;Key Laboratory for Geo-hazards in Loess Area,of Ministry of Natural Resoures,Xian Center of Geological Survey,China Geological Survey,Xian 710054,China)
出处
《山地学报》
CSCD
北大核心
2019年第5期737-746,共10页
Mountain Research
基金
国家重点研发计划项目(2018YFC1504700)
国家自然科学基金项目(41530640)
中国地质调查项目(DD20189270)。
关键词
黄土高原
地质灾害
滑坡
发生规律
斜坡结构
loess plateau
geohazards
landslides
distribution pattern
slope structure
