Abstract:There are many unloaded fissures in elevation more than 1 650 m in the deep left bank of Jinping First Stage Hydropower Station. These fissures occur in the depth from 50 m to 300 m,with large quantity,large scale and long extension,and strike basically parallel with the waterway. The elevation of the dam crest is 1 885 m,and its normal impounded level is 1 880 m. Therefore,these fissures possess adverse impact on safety of the dam after water impound and must be reinforced. The usual grouting or anchor cable technology can not reinforce it better. By the aid of existing geologic exploratory tunnel,anchor tunnel technology and prestressed anchor beam technology maybe have good reinforcement effects. Anchor tunnel technology is a new kind of technology which makes use of existing geologic exploratory tunnels,lays steel and fills concrete in the tunnels to form reinforced concrete columns in order to prevent side slopes from sliding by tensile strength and shear strength of reinforced concrete. Prestressed anchor beam technology is one that is improved from anchor tunnel technology,which divides the anchor tunnel into key reinforcement section and common reinforcement section. The key reinforcement section is often the position where faults or fissures occur while the common reinforcement section is the position where rock mass is good. IV–IV section in the foggy region of left bank is selected for numerical simulation of anchor tunnel and prestressed anchor beam. After comparison of the reinforcement effect of both technologies,it is found that the reinforcement effect of prestressed anchor beam is better than that of anchor tunnel.