Study On The Influence Of Groundwater Exploitation On Pile Foundation Of Deda Railway Bridge

Deda railway is located in Shandong Province,due to the excessive exploitation of underground brine resources along the railway,serious regional settlement problems have occurred in the area,resulting in the settlement of the railway bridge pile foundation in the settlement area.In order to protect the railway traffic safety on the bridge,the performance of railway pile group foundation under the condition of mining groundwater is studied by field test,theoretical analysis and numerical simulation.The main work and research results are as follows:?1?InSAR satellite monitoring technology and leveling technology were used to monitor the settlement of ground and structure in the settlement area of De major railway,and the brine exploitation in subsidence area was monitored.The monitoring results show that the ground,roadbed and bridge have different degrees of settlement between the Deda Railway DK229+800^DK257+500.The most serious settlement is Yingzigou Bridge.The settlement of the railway bridge in the settlement area is caused by excessive exploitation of groundwater.?2?According to the stable submersible flow model,the calculation formula of the settlement of the surface around the non-pressure well is deduced and applied to the engineering example;The numerical simulation method was used to study the ground subsidence caused by pumping,and the results show that the groundwater level and the number of wells are two important factors influencing ground subsidence range and settlement;The influence of stratum subsidence on bearing capacity and deformation of adjacent bridge piles is analyzed,and the results show that when the settlement of soil is larger than the settlement of the pile foundation,the negative friction force is generated in the pile and the bearing capacity of the pile foundation is reduced,which causes the pile foundation to settle and tilt.?3?Based on FLAC^3Dsoftware,the characteristics of settlement and internal force variation of pile foundation of 1#piers in Yingzigou Bridge were studied under the condition of groundwater level decline and pile top load.The results show that with the decrease of groundwater level,the settlement,axial force,friction resistance and negative friction resistance of each pile are increasing and the neutral point is decreased.The water level monitored in August 2015 is regarded as the final water level,the settlement of pile group foundation tends to be stable in August 2016,and the cumulative settlement of pile group foundation is-71.9mm.?4?Based on the control variable method,taking the pile foundation of Yingzigou Bridge as the background,four kinds of pumping condition,such as water level in the well,unilateral or bilateral pumping around the pile foundation,Distance between the well and the pile foundation,and number of pumping wells,are studied.these influence of settlement and internal force on bridge pile foundation is studied and its influence rule is summarized.The results show that the above four factors are the important factors that cause the settlement of the pile foundation and the internal force to change significantly.The results can provide important reference for the settlement of the bridge.