Considering the multiple failure modes of anchor system such as pulling out of grouting mass from surrounding rock

the tensile failure of the pull rod and the shearing failure of interface between pull rod and grouting mass

etc.

applying systematical reliability principle and limit equilibrium method

a direct solution of failure probability of anchor system of rock slope with double slide blocks is proposed based on Monte Carlo sample principle. Meanwhile

taking the time variation of shear strength indices of soft sliding surface c and ? and the erosion of anchor bars into account

a time-variation reliability model of anchor system of rock slope with double slide blocks in consideration of multiple failure modes of anchor is established. The calculation results of examples show that the time-variations of shear strength indices of soft sliding surface c

? and the resistance between grouting body and surrounding rock have great impact on failure probability of anchor system

while erosion of anchor bars has less impact on it.