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.

Under the influences of active ground fissures, the cracking and dislocation of feed pipeline occur from time to time, and cause serious secondary disasters. Based on the engineering background of the proposed ductile iron pipeline crossing the ground fissure in the Southwest Suburb Water Plant of Xi’an City, this paper establishes a numerical model of the 45° pipeline crossing the active ground fissure, and analyzes the internal force response and deformation characteristics of the pipeline under the influence of the ground fissure. The results show that the ground fissure will cause the deflection angle of the pipeline interface to be too large and cause its waterproof failure. Therefore, a method of sectional pipe gallery loading water supply pipeline through ground fissures is proposed, and a numerical model of sectional pipe gallery loading feed pipeline through ground fissures is established. The internal force response and deformation characteristics of utility tunnel and feed pipeline under two working conditions of joint and staggered joint between feed pipeline and utility tunnel, different length of sectional utility tunnel, different locations of ground fissures and different crossing angles are analyzed. It is concluded that the best scheme for utility tunnel loading feed pipeline through ground fissures is the layout of joint between utility tunnel and feed pipeline. The sectional utility tunnel with a single section length of 18 m is adopted to make the ground fissure located at 2/3 of the utility tunnel and cross the ground fissure at a small angle as far as possible. The research results have certain practical significance for engineering construction and disaster prevention of urban feed pipeline crossing active ground fissures.