The optimal composite anchorage structure is constituted by soil nail and groups of fixed-length empty holes that regular setting in the end of soil nail. Empty holes caused a weakened zone in the surrounding rock. The weakened zone is between the reinforced support structure and the surround rock. It changes the original two-medium system into three-medium system. Under the explosion condition

weakened zone is firstly deformed

cracked

crushed or densified; and at the same time

a great deal of blast energy is absorbed. Therefore

the crisis of the reinforced support structure is transferred into the weakened zone. The optimal composite anchorage structure has excellent blast-resistance. The test results of the compression test of optimal composite anchorage structure and single anchorage structure show that the particle acceleration of single anchorage structure is 2.22 times higher than that of the optimal composite anchorage structure. The dynamic strain of the former is 5.30-4.50 times higher than that of the latter. The blast-resistance of the optimal composite anchorage structure is 5.10 times higher than that of the single anchorage structure. Under the limit damage condition

the former is 4.13-3.40 times higher than that of the latter