Experimental Field Study of Movement Charateristics of Rock Blocks Falling down a Slope

The downslope movement of detached rock blocks along steep slopes is an important process endangering the safety of infrastructure along the foot of a slope and on the valley bottom, but only limited knowledge is available on the influence of various factors on the velocity and distance of movement of such blocks. We discuss the influence of the mass and shape of the rock blocks, the steepness of the slope, and the thickness of the overburden on the slope, on the distance of movement of rock blocks which was observed in 256 field experiments with differently shaped blocks from 3 different positions on the slope with a height of 176 m. The statistical evaluation of the results of the field tests shows that the slope condition of gradient and overburden is the main factor, the form of rock masses is the second factor, and the mass is the third of the influencing factors. It is the maximum average acceleration for movement of rock masses when the mass of rock masses is 15≤m < 27 kg, the form of rock masses is flake, the condition of gradient is on average 59.6° and the overburden is basic exposed bedrock and a small quantity of gravel-soil in the experiment condition. It is the minimum average acceleration for movement of rock masses when the mass of rock masses is 9.5≤m < 15 kg, the form of rock masses is rectangular, the condition of gradient is on average 39° and the overburden is gravel-soil and cinder. Then, the foundation for impact energy is provided and the new feasible methods to prevent potential unstable rock masses are put forward.