Abstract: To investigate the effects of various structural parameters on the stress and deformation of utility tunnels under local overload conditions, a three-dimensional mechanical model of a novel utility tunnel structure is established using finite element analysis (FEA) software. The main parameters studied include anchor cable prestress, foundation subgrade reaction modulus, and joint friction coefficient. The findings are as follows: (1) Local overload induces settlement differences between the loaded segments and the adjacent segments, and the deformation at joints between neighboring segments is primarily characterized by differential settlement. (2) The joints of the lower-layer segments exhibit slight opening, with the opening width relatively small (ranging from 1.00 to 2. 00 mm), which satisfies the waterproof requirements of utility tunnel joints. (3) The foundation subgrade reaction modulus is the most critical factor for enhancing the overall longitudinal stiffness of the structure and controlling local settlement. When the subgrade reaction modulus decreases from 20 000 to 2 500 kN/m³, the maximum settlement of the top slab of the upper-layer utility tunnel increases from 3.53 to 17.03 mm, the maximum differential settlement increases from 1.11 to 6.89 mm, the maximum settlement of the bottom slab of the lower-layer utility tunnel increases from 3.05 to 16.55 mm, and the maximum differential settlement increases from 0.81 to 6.88 mm. (4) Increasing the anchor cable prestress between segments can enhance the overall longitudinal stiffness of the utility tunnel to a certain extent. When the prestress increases from 0 to 230.0 MPa, the maximum settlement at the end of the upper-layer utility tunnel decreases from 5.74 to 4.42 mm, and the differential settlement decreases from 2.05 to 0.71 mm. (5) Increasing the friction coefficient between segments has a relatively minor effect on structural settlement and joint differential settlement. When the friction coefficient increases from 0.5 to 0.8, the maximum settlement decreases from 6.06 to 5.22 mm, and the maximum joint opening decreases from 1.45 to 1.36 mm, indicating a limited contribution to improving the longitudinal stiffness of the utility tunnel.

Key words: double-cabin composite utility tunnel, overload, finite element simulation, prefabricated assembly, prestress, longitudinal force analysis