Abstract: Based on the construction of a sewer pipeline built perpendicularly above a existing shield tunnel in Hangzhou,the pipe jacking construction procedure was simulated by software FLAC3D,and verified reasonable after comparing the simulation results with the measured results.By changing the pipe diameter,pipe material and surrounding soil’s characteristic of the shield tunnel,its displacement rule of existing shield tunnel was analyzed.The studies showed that the max vertical and horizontal displacement of the shield tunnel  happened under the sewer pipeline,and the further away from the pipe jacking line,the smaller the deformation;the more diameter of sewer pipeline’s pipe,the more displacements of existing shield tunnel,and the influence of the sewer pipe diameter on vertical displacement was significantly greater than the horizontal displacement;the less elastic modulus of sewer pipe,the more displacements of the shield tunnel;the more elastic modulus of the soil layer,the less displacements of the shield tunnel.

Key words: pipe jacking, shield tunnel, construction monitoring, soil displacemen