兰州市地质灾害类型及其分布规律

Types and Distribution of Geological Hazards in Lanzhou City

在深入分析地质灾害发育现状的基础上,研究了兰州市地质灾害的类型和发育规律。兰州市突发性地质灾害的类型主要有滑坡、崩塌、泥石流和地面塌陷等四种类型。滑坡类型以混合式、中层、小型黄土滑坡为主,崩塌类型以人为黄土崩塌为主。区内滑坡、崩塌呈带(片)状分布,多在特定的岩土体中,集中分布于人为活动强烈的地段,而且分布因地貌而异。兰州市泥石流以小型、沟谷型泥石流为主,其沿河岸呈线状分布,与人类工程活动相关联。地面塌陷属于开采煤矿、人防工程、采砂洞和回填不当引发形成的,造成以点状分布的地面塌陷。

On the basis of investigation and analysis of the geological hazards of Lanzhou city, the types and distribution characteristics of geological hazards are studied. The main geological hazards of Lanzhou city are landslides, avalanches, debris flows and ground collapses. The landslides are predominated by compound medium-depth small loessial type, and the avalanches are dominated by artificial loessial type. Both landslide and avalanche distribute in zones within the particular soil and rocks, concentrate in the areas with strong human activity, and differ with geomorphology. Small-scale gully type is the main type of debris flows which distribute along the banks of streams and are also closely related to human activity. Ground collapses are caused by mining of coals, damage of underground air defense works and sand mining and present dotted distribution.