Water Supply Pipeline Crossing Ground Fissure Zone Model Testing Research

As the lifeline of the city,the underground pipeline project plays a vital role in maintaining the normal operation of the daily life of urban residents.Up to now,a total of 14 ground fissures have been discovered in the Xi'an area,affecting all over the suburbs of Xi'an.As a linear project,underground pipelines cannot be completely avoided.Therefore,the more active ground fissures in Xi'an City pose a serious safety hazard to underground pipeline projects.T-shaped ductile iron pipes are often used as the main water supply pipelines in cities.This article takes ductile iron pipes as the research object,and takes Xi'an ground fissures as the research background.A full-scale physical model test of flexible joint water supply pipes crossing ground fissures under seam-riding conditions is carried out.The main results obtained in the numerical simulation calculation work under the saddle seam working condition and the opposite seam working condition are as follows:(1)Through the analysis of the physical model test process,comparing the stress of the pipeline in different stages of ground fissure activity,it is concluded that the force mode of the water supply pipeline during the ground fissure activity changes from the elastic foundation beam mode to the cantilever beam force mode.(2)In the process of ground fissure activity,the flexible joint of the pipeline can play a good buffering role in the early activities of the ground fissure.In the case of small ground settlement,the flexible joint can buffer the shearing effect of the ground fissure activity on the pipeline.Force effect.After the activity of the pipeline interface reaches the extreme value,stress concentration will appear at the pipeline interface.(3)The stress redistribution of the pipe shaft body under the action of ground fissures in different crossing modes,the distribution of the displacement of the pipe nodes and its change area are determined.It is inferred from this that the pipeline under the seam riding condition is most likely to be pulled out at the pipe joints of the hanging wall,and the pipeline under the seam working condition is most likely to be pulled out at the joint of the ground fissure.(4)Under the same ground fissure activity environment,it is safer to cross the ground fissure by riding the seam than the opposite seam.It is recommended that the method of riding the ground fissure through the ground fissure should be selected in the actual project.The results of this model test have important guiding significance for the construction and prevention of ground fissures in Xi'an underground pipelines.