Zhongguo dizhi zaihai yu fangzhi xuebao (Apr 2022)

Types and characteristics of geological disasters induced by the “7·21” rainstorm in Beijing

  • Haizhi WANG,
  • Qingli ZENG,
  • Bing XU,
  • HU Fugen,
  • YU Miao

DOI
https://doi.org/10.16031/j.cnki.issn.1003-8035.2022.02-15
Journal volume & issue
Vol. 33, no. 2
pp. 125 – 132

Abstract

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Because of rainfall is one of the main inducing factors of sudden geological disasters, by analyzing the temporal and spatial distribution characteristics of typical rainfall and the induced geological disasters, this paper studies the characteristics and laws of different types of rainfall and its induced sudden geological disasters, so as to provide technical support for disaster prevention and reduction under extreme meteorological conditions. Using the method of typical case analysis, this paper systematically analyzes the "7·21" rainstorm with the greatest intensity since the meteorological records in Beijing and its geological disaster data, and studies the response relationship between the number, scale and disaster situation of different types of sudden geological disasters and rainfall and rainfall intensity, This paper focuses on the threshold of short-term heavy rainfall debris flow in the mountainous area of western Beijing.The results show that with the increase of the distance from the rainfall center, the number, type and scale of sudden geological disasters gradually decrease, and the rainfall intensity is the key factor inducing the occurrence of sudden geological disasters. The triggered rainfall and rainfall intensity of different types of sudden geological disasters are obviously different. The triggered rainfall intensity and rainfall of debris flow and landslide are higher than that of collapse. The cumulative rainfall threshold of debris flow induced in Beijing mountainous area is 187.4−257.2 mm, and the hourly rainfall intensity threshold is 51.2−62 mm. Based on the research results, the real-time data of debris flow triggered by “7·21” are compared with the previous critical rainfall of debris flow based on average rainfall intensity, and the critical rainfall prediction model based on average rainfall intensity in Beijing is modified, so as to provide technical guarantee for improving the accuracy of early warning and prediction of geological disasters.

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