Control of Strata Deformation in Subway Interval Tunnels Crossing a High‑Speed Rail Shield Tunnel at a Short Distance

摘要

The construction of subway interval tunnels at a short distance from existing buildings and engineering structures in cities isoften a high-risk project. This research discusses subway interval tunnels crossing a high-speed rail shield tunnel at a shortdistance based on numerical simulations and on-site monitoring. The deformation patterns of the interior of tunnel, ground,and shield segments are analyzed, and the principle and function of reinforcement measures for deformation control arepresented. The results indicate that constructing a temporary inverted arch using bolting and shotcreting as per the benchmethod has higher integral stiffness, and thus, the foot-locking effect of anchor pipes to reduce strata deformation is fullyutilized. The deformation of upper high-speed railway shield tunnel segments induced by the construction of subway intervaltunnels primarily occurs within a distance three times the diameter of the tunnel. Thus, this is the key area to install advancedsupport to control tunnel deformation. A compound advanced support approach including pipe sheds and deep-hole groutingis proposed that can exert the arching effect of deep-hole grouting and beam effect of pipe sheds to control strata deformation.