Abstract: Taking the Yanjiagou landslide in Zichang county of Yan′an as an example,this paper analysed the developing features and reactivation mechanism of the valley-type landslides.The fundamental cause of the reactivation of the valley-type loess landslide is thought to be the continuous erosion on the landslide body,which produces a new free face at the toes of landslides.Countermeasures based on incorporation of side retaining walls and water drainage are proposed to realize low-cost remediation of ...