Abstract: Open pit dumps mainly face the serious threats of landslides and mudslides.The stability problem of dumps is not only a safety issue but also an economic issue.Heap loading and rainfall are the two most important factors affecting the stability of dumping site.However,the accurate and efficient monitoring and early warning of dumping in the dumping site have always been a major problem,and it is urgent to carry out research on some related aspects.In view of the above problems,the No.2 full section high dump at Nanfen open pit iron mine was taken as the research object,and a monitoring network composed of monitoring optical fibers was used to carry out some heap loading and rainfall simulation experiments on the similar physical models of No.2 full section high dump.Based on the numerical simulation of the dump deformation under different loading conditions and the scanning results of the model materials under the influence of rainfall,the deformation analysis of different positions of the dump under different loading conditions and different rainfall conditions was carried out by means of physical,numerical simulation and cross integration of macro and micro multiple means,and finally the temporal and spatial evolution laws of the dump deformation under different loading and rainfall conditions were obtained.It is concluded that the dump deformation is positively correlated with the increment of loading,but the slope deformation sensitivity decreases with the increase of depth.It is positively correlated with the unit rainfall duration,but with the total rainfall duration,drainage consolidation occurs in the dump,and the deformation decreases,making the two negatively correlated.The numerical simulation results show the process of forming a through sliding surface of the dump slope under the action of heaps.The microscopic analysis results show the formation mechanism of the potential sliding surface of the dump slope under the influence of rainfall.The sliding surface is precisely positioned according to the experimental results of physical model.Finally,based on the results of laboratory physical model experiments and numerical analysis,it is suggested to use optical fiber sensing technology as a monitoring method for slope deformation and instability in the dumping site