The Analysis Of The Effect Of Underground Tunnel Construction On Bridge Structure

In urban subway construction, the blasting method and the shield method is widely used by its unique advantages. Therefore, in the construction process of formation and the failure of disturbance and impact of bridge structures is always a problem which people focus on. Analyzing dynamic bridge structures under the action of blasting and dynamic response of shield tunnel construction in the process of strata subsidence, deformation law of piles and soil, etc., to guide the construction and control measures have practical significance.Based on the 208 block weitai bridge under construction in dalian subway interval and 202 blocks between railway bridge project as the background, The effect of the blasting construction and the shield construction of road and bridge structures were studied in detail and combining three-dimensional elastic-plastic finite element program to establish simulation model, and analyzed with data collection and monitoring. The main research contents and results are as follows:(1)The blasting dynamic load of piles and soilThe attenuation of vibration velocity of blasting seismic wave attenuation area and in different directions are different, it is concluded that soil near the explosion source by shock blasting load is big, but its fluctuation time is short, and explosive source far soil under blasting load is small, but the wave vibration long duration and large damage. Due to multiple reflections of blasting shock wave strong, the damaging of bridge pier structure is relatively large, single blasting cumulative damage is small, but many times blasting bridge pier causes internal cumulative damage. In fixed-point monitoring shows that the vertical monitoring its vibration velocity at different depth of the peak to peak time and size are different, the closer the explosive source, the greater the peak of disturbance, the shorter the time. Close blasting will have a great influence on the safety of existing tunnel lining, the existing tunnel lining to meet critical side arch for the weak area of the waist, need to focus on prevention in site construction.(2)Pile soil in shield tunnel construction in the process of changeIn simulation, first of all, to analyze the sensitivity parameters of shield construction, and sums up as the soil pressure, grouting pressure, through the hard and soft soil layer and soil different pavement deformation law; Second, in the shield construction across the railway bridge, sums up the law of soil lateral deformation of the soil loss in the vertical deformation, formation damage road surface analysis, and compared with field monitoring data. In the analysis of piles and soil on the pile of proximity of judgment, and through the change of the friction resistance reflect the differential settlement between pile soil.