The affecting factors and sensitivity of the displacement fields produced by the shield tunneling across the ultra-near tunnel obviously differ from that of the general construction. Combining the metro tunneling examples within ultra-near distance (1.05 m)in Shanghai

It is found that the earth pressure varies significantly while shield approaching to adjacent metro tunnel in operation situated overhead. Based on the principles of tunnel loading model and theory of elasticity a

theoretical formula of earth balance pressure of shield was deduced and a so-called “step control strategy” was concluded which was successfully applied in a typical project of Shanghai metro tunnel line No.4 of which the maximum displacement was controlled within 5 mm. The field measurements of earth pressure proved to be at good coincidence with the theoretical values.