LONG RUNOUT ROCKFALL-LANDSLIDES AND THEIR FORMING CONDITIONS

The geological event of long runout rockfall-landslide can cause great damages and broader coverage,which are followed closely by engineering and technical personnel.The Wenchuan Earthquake,happened in May 12, 2008,induced tens of thousands of landslides.Though the number of long runout rockfall-landslides was not high,they did greater damage than the other types of landslides.Comparing with general landslides,the forming conditions of the long runout rockfall-landslide are studied.In order to predict its severity and range and provide basis for homeland planning and preventive treatment design,this paper summarizes its characteristic and comprehensively analyses the factors influencing its high speed and long distance.The paper is based on practical engineering experience and widely collection of studies about the long runout rockfall-landslides at home and abroad.Earthquake,ground water,and mining activities can cause the landslide instability and make it active.The paper proposes that the long runout rockfall-landslide must exist the following three conditions: namely large-scale sliding masses,cut export overhang and the terrain available for geology body to movement.It provides important research contents for further prediction of the space distribution of the long runout rockfall-landslide.