Study On Blasting Construction And Vibration Control Of Underground Pipelines Under Urban Metro Tunnels

In recent years,with the continuous development of the economy,urbanization has become increasingly serious.In order to alleviate the traffic pressure in the large and medium-sized cities across the country,large-scale construction of the subway has become a trend.In the construction process of urban subways,the problem of underground subway lines crossing underground complex pipelines is often encountered,and the impact of preventing blasting vibration on urban subway tunnels has become one of the major concerns.Based on a project of Qingdao Metro and relying on the water supply pipeline underneath it,this paper mainly focuses on the unique geological conditions and characteristics of underground structures in Qingdao,and actively seeks effective construction methods to reduce the adverse effects of blasting vibration on underground pipelines.And summed up the force variation law and attenuation characteristics of the pipeline,and seeking this construction method has certain reference significance in other areas with similar conditions.The main research contents and research results are as follows:(1)This paper analyzes the research results of the relevant fields at the present stage,discusses the propagation and attenuation laws of blasting seismic waves,and concludes a variety of damping control methods,and uses this as a theoretical basis and basis for further research.The foundation.(2)Conducting on-site test and scientific monitoring around the research content,based on the monitoring results and the objective environment on site,using the Sadowski’s empirical formula and linear regression analysis theory,and using regression analysis to obtain the Sadolphs in line with the on-site geological conditions.The base vibration velocity attenuation formula provides a reliable tool for the subsequent vibration velocity prediction,and also provides a scientific reference for the on-site blasting construction.(3)Using the ANSYS/LS-DYNA finite element simulation software,a finite element analysis model was established to simulate the force of the buried water supply pipeline under the action of blasting seismic waves,and the force variation and attenuation characteristics of the buried pipeline were summarized.Wait.(4)Based on the above research results,it is proposed to optimize the blasting scheme by adjusting the parameters of the hole network,increasing the number of boreholes in the gutter,and changing the detonation mode of the gutter hole.The feasibility and effectiveness of the scheme are verified by the monitoring results.The scheme successfully reduces the blasting vibration speed by 41.9%～69.23%.This research result has a strong reference for the subsequent blasting construction.