Influence And Control Of Metro Construction With Mining Method On Adjacent Pipelines

Metro construction may pose a potential threat to existing buried pipelines.Metro tunneling disturbs the ground,and may cause additional deformation and stress in the nearby pipelines,which,if excessive,would affect the normal operation and safety of the pipelines.It is needed to study the influence of metro construction on adjacent pipelines and take proper control measures in order to ensure metro construction proceeds safely and orderly without affecting normal operation of the pipelines.With the construction projects of Beijing Metro Line 5 and Line 10,especially the Huangzhuang subway station of Line 10 as the background,a study is carried out about the influence of metro-construction induced ground movements on adjacent pipelines. The ground settlement,the pipeline response and the main influence factors for tunneling with the Drift-PBA method are studied by using numerical simulation and field measurement.Regression analysis of the field measured ground settlements induced by shallow metro station constructions in Beijing is conducted to acquire empirical estimations of the ground surface settlement trough width and the ground loss ratio.A simplified method using deformation as the control index for evaluating the degree of safety of buried pipelines is put forward.A systematic procedure for control of metro tunneling effects on adjacent pipelines is put forward.The main conclusions are as follows:1.Patterns of pipeline responses,including settlement,joint rotation and pullout, strain and soil-pipe interaction,induced by metro construction with mining method are analyzed and summarized.2.The main influence parameters for pipeline deformation,including the relative positions between tunnel and pipeline,the tunnel span and the flexural rigidity of pipeline,are studied.3.A simplified method for conservatively and quickly evaluating the safety of buried pipelines is put forward.4.A regression analysis of the field measured ground settlements is conducted to acquire empirical estimations of ground surface settlement trough width and ground loss ratio.5.Control criteria and measures for buried pipelines are summarized.