四川省甘洛县山体滑坡应急调查与成因机制分析

Emergency investigation and formation mechanism of landslide in Ganluo County,Sichuan Province

2019年8月14日四川省甘洛县苏雄乡埃岱村成昆铁路2号隧道口突发山体滑坡,造成17名铁路工人遇难。为了确保应急处置安全、科学、高效的实施,通过无人机低空航测和现场调访、地质测量等方法对“8·14”甘洛滑坡进行了现场应急调查,在获取了滑坡区地质条件和滑坡的形态特征的基础上,进行了滑坡成因分析。结果表明:滑波区斜坡受河谷下切卸荷的浅表生时效变形、物理化学风化以及工程扰动等因素的长期作用,斜坡岩体破碎,稳定性差,在强降雨和侧缘冲沟泥石流冲蚀作用下在高位突然失稳下滑,形成高速滑坡,破坏力巨大。在极端降雨情况下,冲沟泥石流的冲蚀作用对坡体表层岩土体的扰动极易引发滑坡灾害,这类滑坡具有极强的隐蔽性、突发性和破坏性。

On August 14,2019,a sudden landslide occurred at the entrance of Chengdu-Kunming Railway No.2 Tunnel in Adai Village,Suxiong Township,Ganluo County,Sichuan Province,causing seventeen railway workers deaths.To ensure the safe,scientific and efficient implementation of emergency treatment,we used aerial drone surveys,site visits and geological surveys to investigate the geological conditions and morphological characteristics,and analyzed the formation mechanism of the"8·14"Ganluo landslide.The results showed that due to the time-dependent deformation of slope surface resulted by river valley incision,physical and chemical weathering as well as disturbances of construction,the rocks on the slope area had been fractured and the slope itself became unstable.Eventually,triggered by heavy rainfall and the erosion of a side groove-type debris flow,the landslide lost stability.It is concluded that under extremely heavy rainfall,disturbances on rocks and soil on the slope surfaces caused by the erosion of groove-type debris flows are likely to cause landslides that are highly concealed,abrupt,and destructive.