Abstract: To ensure safe and efficient construction in the lithologic interface area of deepburied tunnels bored by tunnel boring machines, field  investigations and microseismic surveys are comprehensively employed to study the characteristics of surrounding rock damage and microseismicity in the axial lithologic interface area. On this basis, the support technologies for the surrounding rock damage in the lithologic interface area are examined. The results are as follows: (1) Owing to the stress concentration in the lithologic interface area, the surrounding rocks are prone to damage after excavation and unloading. The characteristics of "hard" on the south and "soft" on the north of the surrounding rocks cause different types of damage, distributed on both sides of the tunnel with the alteration zone as the boundary, and the damage distribution has obvious regionality. (2) There are good spatial correlations among rockburst, collapse, and microseismicity. (3) When the rockburst grade is low, the structural collapse should be preliminarily considered when employing a support method. As the rockburst grade rises, the rockburst should be gradually considered in the support method.

Key words: tunnel bored by tunnel boring machine, rockburst; collapse, lithologic interface, failure mechanism, support method[