Mechanics characteristics of cemented filling and surrounding rock

In order to ensure the safety of filling stope and ore mining efficiently,it is necessary to study the interaction between the filling and surrounding rock in different strength periods,which influences the stability of filling stope. The paraffin was selected as the contact material to simulate the early strength of the filling body,and also considering the complexity of the stress environment in the contact zone,the non-uniform stress in the contact zone between the wall rock and the early-strength backfill was simulated. In order to effectively characterize the regional instability in the contact zone and realize the transformation from qualitative analysis to quantitative evaluation,the PVC plastic foil was placed on the contact face between the surrounding rock and the early strength filling body. Combined with the micros- copy imaging,electron microscope scanning,AE monitoring and strain monitoring,the laboratory experiment of the in- teraction between the surrounding rock and the early strength filling body under different load conditions was studied. The strain change,crack growth deformation evolution,stability failure of cemented backfill and surrounding rock complex were monitored and analyzed. The results show that the deformation of the contact zone increases rapidly,the strain value fluctuates greatly and the abrupt change is obvious. After loading,the paraffin in the contact zone shows three different damage characteristics:one is spiral damage,the second is the parallel type of damage,the third shows the characteristics of cross-damage,and the strain around the contact zone shows a steady increasing trend. The results also show the complex mechanical and deformation characteristics of filling body and surrounding rock,which has a certain guiding significance to ensure the stability of the stope with the early strength filling body. The synchronization between crack propagation and internal damage is realized. The study provides a research idea for further studying the mechanical properties of backfill and surrounding rock complex under two-dimensional and three-dimensional loads.