Study On The Influence Of Crossing Engineering On The Existed Elevated Line Of Urban Rail Transit

In recent years,urban infrastructure is in a large-scale construction and development period,with increasingly intensive underground pipelines,metro tunnels and other underground structures.At the same time,with the rapid development of urban rail transit and expansion of railway network,the construction of crossing engineering,adjacent to the existed elevated line of urban rail transit,frequently emerges.The crossing engineering construction inevitably brings deformation and displacement of ground,thus producing additional internal force and deformation of bridge superstructure,and even affecting normal operation of elevated line.In order to ensure the normal and safe operation of the existed elevated line,the status investigation and evaluation for elevated line,making the control standard for vertical displacement of girder and foundation settlement,and making protection measures of construction should be carried out before crossing engineering construction.Recently,the relevant technical standards of crossing engineering construction adjacent to elevated line are not mature and standard.For the purpose of crossing engineering construction proceeding in an orderly and safe way by the premise of the existed elevated line protection,the key technology's researching on influence of crossing engineering on the existed elevated line is an urgent need.This thesis studies on crossing the existed elevated line of urban rail transit by using theoretical analysis method,makes clear influence morphology and action mode of crossing engineering on the existed elevated line,and gives the influence area classification.By using numerical calculation analysis of single pier settlement and double pier settlement,caused by crossing engineering,trait and regulation of the existed elevated bridge superstructure's deformation is obtained.From the perspective of the existed elevated line protection,the principle of making control standard are "zone classification,grades classification and stages classification",and the method of making control standard are based on investigation and evaluation of present situation, analysis of influence prediction,and similar engineering experience.From two respects as load capacity control and technical requirements of line,this thesis gives the control standard of vertical displacement of girder and foundation settlement for the existed elevated line,and suggests that control standard should be modified,based on the result of status evaluation.Finally,from three aspects of construction reinforce technology, construction process control and emergency measures,control measures are made. The control standard and control measures,proposed in this thesis,have some reference value for the problem of crossing engineering construction adjacent to the existed elevated line,and are helpful to similar engineering problem treatment.