Abstract:

A 3D elasticplastic finite element model is established and nonlinear static stress and strain analysis is made so as to analyze the influence of the construction of the overlapping tunnel on the ground surface and surrounding rocks of the existing tunnel under different intersection angles. Conclusions drawn are as follows: The shape of the contour of the ground surface settlement is similar to the projection of the overlapping tunnel; As the intersection angle increases, the crown (invert) settlement of the existing tunnel at the overlapping point reduces gradually, however the change value is small; When the intersection angle ranges from 15° to 45°, the change rate of the deformation of the surrounding rock of the existing tunnel along the tunnel axis increases. The research results not only can provide reference for the plan and design of similar overlapping tunnels in the future, but also can provide reference for the optimizing of the shield boring parameters so as to achieve scientific, rational, safe and highquality tunneling.

Key words: Metro, overlapping tunnel, intersection angle, shield method, strata deformation