Study Om Dynamic Characteristics Of Blasting Construction And Train Vibration Of Subway Crossing

With the improvement of urbanization in China,more and more cities begin to build subways to ease traffic and improve land utilization.In the process of subway construction,as an important part of subway section construction,the construction process of subway transverse passage is crucial to the stability and safety of the main subway tunnel,which has been widely concerned by scholars at home and abroad.Therefore,based on the construction project of horizontal passage of Harbin rail transit line 2,this paper adopts a variety of research methods to study the stability problems caused by vibration.The numerical model of the transverse passage is established to study the lining structure stability of the transverse passage under blasting excavation and train vibration load.Based on the correction of peck's formula,a formula for predicting the surface settlement during the construction of the transverse passage was proposed,which provides an important theoretical basis for predicting the surface settlement in Harbin area.The main research contents are as follows:(1)Mechanical mechanism analysis of blasting construction process of cross passage.Based on the finite difference software FLAC 3D,the construction numerical model of the transverse channel was established to study the lining stress,strain and vibration velocity caused by the blasting excavation of the transverse channel.The influences of construction Angle,construction blasting method,buried depth and surrounding rock grade on the stability of transverse tunnel are analyzed.(2)Analysis of lining stability of transverse passage under train load.By using numerical model,the displacement stress,velocity and acceleration of lining caused by train running vibration are studied.The influence of train on train track under different construction angles,train speed,tunnel depth and surrounding rock grade is simulated.(3)Monitoring data analysis.Through on-site monitoring,the settlement law in the process of blasting construction and train operation is studied.With the construction of the transverse passage,the surface settlement above the transverse passage is a phenomenon of slight uplift and then settlement on the whole,and the effect of dynamic load on the surface settlement is small.(4)Surface settlement formula modified.Based on Peck formula and in combination with Harbin metro line 2,the surface settlement data during the construction of the transverse passage were statistically analyzed.By introducing the maximum surface settlement correction coefficient and the width correction coefficient of the settlement trough,the prediction formula of surface settlement caused by the construction of the horizontal passage in Harbin area is put forward.