Abstract: Based on meteorological monitoring data, the causes of the disaster event of mountain collapse over Fangshan district in Beijing on 11 August 2018 (hereinafter using abbreviation“8·11” event) were analyzed. The results show that the west Pacific subtropical high (WPSH) was more stronger and the position was northward and westward, which induced more rainfall and higher temperature, the cumulative effects of rainfall and temperature provided favorable weather condition for this  collapse event. The deep soil moisture increased and remained due to positive cumulative precipitation anomalies. Besides, the “baking” effect of high temperature weather on the collapse disaster should not be ignored as well.Thermal expansion and cold contraction caused by the acute change of dry-wet cycle induced variations in slope stability of surface layer, which could influence the stability of rock and soil mass.

Key words: “8·11” event, mountain collapse, geological disaster, meteoropogical causes

摘要： 利用气象监测数据，分析2018年8月11日北京市房山区较大规模崩塌地质灾害事件（简称“8·11”事件）的气象成因。结果表明，西太平洋副热带高压异常偏强、偏西且偏北，导致北京地区降雨和高温日数比常年同期明显偏多，二者的累积效应为崩塌事件的发生孕育了非常有利的气象条件。持续性强降雨引发的长期渗透作用使得深层土壤含水量增加并稳定维持；高温天气的“烘焙”效应对崩塌灾害的作用也不容忽视。干湿循环的剧烈变化引起的热胀冷缩作用使得地表层斜坡的稳定性发生变化，从而影响岩土体的稳定性。

关键词: “8·11”事件, 崩塌, 地质灾害, 气象成因