Kong Jiaxu, Zhuang Jianqi, Peng Jianbing, et al. 2021. Spatial and temporal distribution characteristics and risk simulation of loess micro geomorphic disaster chain in Laolang Gully, Lanzhou [J]. Journal of Engineering Geology, 29(5): 1401-1415. doi: 10.13544/j.cnki.jeg.2021-0435.
    Citation: Kong Jiaxu, Zhuang Jianqi, Peng Jianbing, et al. 2021. Spatial and temporal distribution characteristics and risk simulation of loess micro geomorphic disaster chain in Laolang Gully, Lanzhou [J]. Journal of Engineering Geology, 29(5): 1401-1415. doi: 10.13544/j.cnki.jeg.2021-0435.

    SPATIAL AND TEMPORAL DISTRIBUTION CHARACTERISTICS AND RISK SIMULATION OF LOESS MICRO GEOMORPHIC DISASTER CHAIN IN LAOLANG GULLY, LANZHOU

    • Loess caves and landslides are micro-geomorphic landscapes under the unique erosion of the Loess Plateau. They reflect the chain process of rapid geomorphic evolution. They have the characteristics of wide distribution and high development density,and can seriously threaten the safety of human settlements in Northwest China. This paper takes Laolang gully small watershed as the research object,adopts field investigation,GIS spatial analysis,UAV mapping and numerical simulation. This paper carries out the research on the spatial-temporal distribution characteristics and risk of loess micro geomorphic disaster chain. The results show that the numbers of loess caves,landslides and shallow gullies developed in Laolanggou study area are 134,38 and 81 respectively. The density of loess caves is about 159/km2,accounting for 1.88% of the total area of the study area. The loess caves are mostly located in the TWI high concave terrain area,and are arranged in a linear distribution,which is closely related to the development of shallow gullies. The results of five nuclear density estimates from 2001 to 2021 show that the high density centers are located in the west slope,with an area of about 5.91×104 m2. Its spatial agglomeration degree of long axis,short axis,area,elevation and perimeter is the highest. The evolution model of loess micro geomorphic disaster chain can be summarized as primary geomorphic stage,early erosion stage,accelerated erosion stage,erosion breakthrough stage and then local destruction stage. The cave environment aggravates the degree of water infiltration,which is more likely to cause landslides. The simulation results show that the potential landslide movement can cause serious damage to the terrace buildings,and the affected area is about 2.02×104 m2,the landslide movement process is 150 s,the average accumulation thickness is about 9.2 m,and the maximum movement distance is about 651 m. This study is a beneficial exploration and attempt to reveal the development law of loess caves and its disaster chain effect,and provides a reference for urban disaster prevention and reduction in the Loess Plateau.
    • loading

    Catalog

      /

      DownLoad:  Full-Size Img  PowerPoint
      Return
      Return