Suitability Analysis of Assembly Underground Utility Tunnel through Active Ground Fissures

In the area where ground fissures are widely distributed, the suitability of the assembly underground utility tunnel to pass through the active ground fissures is not clear. In order to study the stress and deformation characteristics of assembly underground utility tunnels under the action of ground fissures, three-dimensional finite element models of assembly underground utility tunnels crossing the ground fissures were established. Four different settlement conditions of 10cm, 15cm, 20cm, and 25cm and four different intersection angles of 45°, 60°, 75°, and 90° were set. The numerical simulation and analysis are carried out, respectively. The calculation results show that with the increase of ground fissure activity, the deformation and longitudinal stress of the utility tunnel increase. When the settlement is close to 20cm, the maximum longitudinal tensile stress of the bottom plate of the utility tunnel reaches the tensile limit of concrete, which is located near the ground fissure in the footwall. The smaller the intersection angle between the ground fissure and the utility tunnel, the smaller the maximum longitudinal tensile stress of the utility tunnel, but the torsional effect is obvious. In the site with weak ground fissure activity, the prefabricated underground utility tunnel crossing the ground fissure shows better suitability for uneven deformation. The research results are of great significance to the study of failure mechanism and disaster prevention of assembly utility tunnels under the action of ground fissures.