Abstract: XidanLingjing Bystreet section of Beijing Metro, which is constructed by mining method, crosses underneath overpasses, roads, utility lines and air defense works. The risks in the construction of the tunnel are identified, analyzed, assessed and coped with. The pile foundations of the overpass are underpinned and the ground around the pile foundations is reinforced by grouting. The spacing of the lattice girders, the advance small duct and the connection plate of the lattice girders are optimized and foot locking bolts are added. The deserted slope protection piles and air defense works that interfere into the tunnel are broken and consolidated. In the end, the risks have been brought under effective control and the tunnel has been completed successfully.

Key words: Beijing Metro, sandy cobble strata, running tunnel, mining method, risk, pile foundation underpinning, grouting reinforcement