Analysis of Construction Impact Patterns of Shield Tunneling Beneath Utility Corridor

Due to the limitation of geological conditions and comprehensive development and utilization of underground space, underground engineering sometimes inevitably involves close spatial intersection, with shield tunneling beneath utility tunnels being a common challenge in such engineering projects. This study utilizes the numerical simulation software FLAC3D to analyze the displacement of the pipe corridor and the ground settlement during shield tunneling beneath an underground utility tunnel. The results indicate that during the entire shield tunneling process, the peak values of displacement and stress occur in the Z direction ( vertical direction) . In terms of displacement changes, the Z direction exhibits two types of displacement patterns: uplift and settlement. The maximum displacement in certain regions reaches 3. 34 mm and 2. 76 mm, while the displacement in the X and Y directions remains about 0. 5 mm. In terms of stress changes, the maximum stress in the Z direction is 2. 0 MPa, while in the X and Y directions, the maximum stress is 0. 25 MPa and 0. 5 MPa, respectively, with the stress concentration coefficient of approximately 1 and 2. During the process of sewage interception pipeline crossing the utility tunnel, the key risk areas mainly include the central part of the upper slab, the bottoms of the two compartments, and the partition walls. The maximum subsidence of the upper slab is in the middle of the pipe trench intersection influence range (X = 47 m) , and the maximum uplift of the right and left compartment bottoms is in the rear of the intersection influence range (X = 51 m) , and the left compartment uplift is greater than the right compartment. The stress concentration area of the pipe trench is in the front part of the partition walls in the intersection influence range (X = 43 m) . To ensure the structural integrity of the utility tunnel, it is necessary to monitor the displacement and stress changes in this area during the actual shield tunneling process and adopt foundation cutting and reinforcement measures when necessary.