Influence of pumping from confined aquifers on deformation of adjacent existing tunnels

The pumping of confined aquifers will cause the coupling effect between seepage field and stress field, which is easy to cause additional deformation to the adjacent existing tunnels and threaten the safety of the structure. Therefore, it is of great engineering significance to accurately evaluate the influence range of pumping and reveal its deformation mechanism to ensure the safety of adjacent tunnel structures. A finite element model is established with Plaxis 3D finite element software to explore the deformation and displacement characteristics of tunnels at different positions after pumping. The results show that after the completion of pumping, with the increase of buried depth, the settlement and horizontal displacement of the tunnel show a non-monotonic development trend, and the overall displacement peaking at the aquifer and the aquiclude. With the increase of the distance from the pumping well, the settlement of the tunnel decreases gradually, and the horizontal displacement increases first and then decreases. Combined with the deformation control standard of subway tunnel, the influence domain division standard of displacement contour is constructed, and the definition standard of engineering protection zone based on critical displacement threshold is proposed, which provides theoretical guidance for practical engineering.