A new algorithm method about the possible motion path of rockfall is proposed

which should be clear in the design of rockfall prevention engineering.According to the rockfall motion state

when the rockfall goes through the different calculation interval

the calculation intervals are divided into seven classes.In the calculation intervals

the motion process is divided by three types including flight

rolling and crash

and the conversion conditions of the rockfall among the three motion types are defined.First

the calculation intervals are classified by the slope surface characteristic;then the motion path of rockfall is calculated in each calculation interval orderly

and the type of the calculation interval should be determined at the same time;so the motion path is obtained at last.For simulating the motion randomness of the rockfall

the key parameters in the calculation are assumed to obey uniform distribution.The correctness of the algorithm is verified by a numerical example and the seven kinds of calculation intervals and the results of 20 random calculations are also shown in the example.