Abstract:The approaches of determining the joint persistence ratio of rock mass by dynamic programming and genetic algorithm methods are described based on a simple test example. In a simulated joint map,both methods are able to find the combinations of joint and rock bridge associated with the least comprehensive shear force. It is found that the two methods gave virtually the same results. The influence of two different shearing terminal conditions is investigated on the calculation results. The joint persistence ratio obtained by fixing both ends of shear path is smaller than that without fixed ends,and the comprehensive shear strength with both fixed ends of shear path is larger than that without fixed ends.