Abstract：Engineering practices show that the existence of underground structures or obstacles severely influence the distribution of displacement produced by shield tunneling across them. To analyze and predict magnitudes and the characteristics of the ground deformation induced by shield tunneling across the adjacent underground objects, the boundary element method is deduced considering the underground objects as the elastic boundary. According to the small deformation hypothesis of the elastic theory and coordination conditions of elastic boundary，the ground displacement fields can be obtained by superposition of the displacement fields produced by shield tunneling and reaction forces on the elastic boundary. The displacement caused by reaction on the elastic boundary can be achieved by the theory of Winkler elastic foundation. Analytical results based on the above mentioned principles indicate that there are great differences about the characteristics of the ground displacement fields with/without considering the elastic boundary. The existence of the underground objects obstructs the propagation of the ground movement and makes the accumulated displacement near them. So，there is an important signification in accurate prediction and precontrol of the displacement fields subjected to the adjacent advance of the shield by considering the effect of the elastic boundary. In practice，the critical control distance can be calculated by the proposed method，which could be employed in precontrol of shield construction and secure the safety of adjacent protected objects.
