English：

Taking the parallel long diversion tunnel of a hydropower station as an example, the applicability, of drilling and blasting method and TBM construction method, is studied by comprehensive comparative analysis of tunnel size, engineering geological conditions along the line, construction period and excavation slag reuse, etc. TBM construction method has obvious advantages in the construction of long tunnel projects,which are difficult to increase the construction adits；while drilling and blasting method has stronger applicability in the construction of tunnel excavation projects with large section and complex geological conditions. By arranging appropriate construction adits, the construction section of the diversion tunnel can be effectively increased to speed up the construction progress with drilling and blasting method. However, the particle size of the slag produced by TBM construction is too small to meet the requirements of the reuse of the slag as aggregate. In addition, due to the large diameter of the diversion tunnel excavation, complex regional geological conditions, and the lack of relevant engineering reference experience, once a construction accident occurs, it is difficult to quickly solve, thus increasing the uncertainty of the construction period. Therefore, drilling and blasting method is recommended as the main construction excavation method of the parallel large diversion tunnel of the hydropower station.