Dynamic Response Of Adjacent Pipelines During Blasting Construction And Research On Vibration Reduction Measures

Drilling and Blasting Method has been widely used in the construction of urban rock subway tunnels due to its strong adaptability to geological conditions and low cost of excavation.However,there are often many complex buried pipelines in the construction area of urban subway tunnels.This requires timely monitoring the dynamic response of pipelines during blasting construction and reducing the impact of blasting vibration on the normal use of pipelines.However,due to the fact that the pipeline has a certain buried depth,etc.,the vibration velocity of the surface above the measured pipeline indirectly reflects the vibration velocity of the pipeline,and there is usually a difference between the two.This paper studied the reflection and transmission laws of blasting seismic waves,analyzed the dynamic response of adjacent buried gas pipeline and surface measurement points in tunnel blasting process by numerical simulation method,proposed the prediction formula of vibration velocity of blasting seismic waves at surface.And proposed corresponding vibration reduction measures.The main work is as follows.(1)Based on the propagation theory of blasting seismic waves,it analyzed the relationship between incident wave and transmitted wave in particle vibration velocity and amplitude when the blasting seismic wave was normally incident or obliquely incident.(2)Based on ABAQUS platform,it established the dynamic analysis model of buried pipeline under blasting.The model comprehensively considered the application method blasting load,viscous-spring artificial boundary setting,JWL equation of state,selection of explosive parameters,and selection of material dynamic parameters.Taking the single-hole blasting model as an example,it discussed the rationality of the model parameters and their settings.(3)By changing the different parameters(elastic modulus,Poisson's ratio)of soil layer and subgrade concrete layer,the buried depth and horizontal position of pipeline,it analyzed the vibration response law of the pipeline and its surface measurement point under blasting load by numerical simulation,analyzed theoretically the reflection and transmission of blasting seismic waves between the upper and lower interfaces of a certain thickness of roadbed concrete and its superposition at the surface measuring points.The prediction formula of the vibration velocity of surface measuring points was proposed.By comparing the vibration velocity of the measuring point obtained by the prediction formula with that obtained by numerical simulation,the reliability of the prediction formula of the vibration velocity of surface measuring points was verified,which provides a reference for studying the relationship between the vibration velocity of buried pipeline and that of the surface measured points above pipeline.(4)Methods of setting one row of damping holes,two rows of damping holes and damping groove arranged around the tunnel were selected to reduce the influence of blasting vibration on the adjacent buried pipeline.The numerical simulation results show that the vibration reduction effect of the damping groove is obvious.