Abstract: Multiple road excavations in tunnels for pipeline laying cause traffic congestion and high costs. To address this challenge, a hybrid precast utility tunnel (HPUT) composed of composite slabs using reinforcement connection is proposed, characterized by ease of lifting, reduced on-site casting, reliable connections, good integrity and waterproof performance. Based on ABAQUS software, a finite element (FE) analysis model of the HPUT under horizontal loading is established. To verify the rationality of this model, a middle connection test is conducted on the HPUT, and the results show good agreement with the FE analysis. On this basis, a further FE analysis of the overall structure of the HPUT is conducted, primarily focusing on haunch height and axial compression ratio. The results demonstrate the following: (1) The failure mode of the overall structure is bending failure. (2) The peak capacity of specimens ranges from 200.5 to 298.6 kN, and the inter-story drift angles range from 1/43 to 1/27. (3) Compared with specimens without haunches, specimens with haunch heights of 150 mm and 250 mm show increases in peak bearing capacity by 24.4% and 39.7%, respectively, and increases in peak displacement by 49.3% and 60.1%, respectively; When the axial compression ratio increases from 0 to 0.05 and 0.10, the bearing capacity of the HPUT increases by 10.3% and 19.7%, respectively, while the peak displacement decreases by 5.2% and 18.6%, respectively. It is concluded that the overall structure of the HPUT exhibits substantial bearing capacity and commendable deformation capacity.

Key words: hybrid precast utility tunnel composed of composite slabs, composite slabs connected by reinforcement, finite element analysis, mechanical properties