| Metro trains are under vibration load for a long time,the foundation under the geological conditions of mainly silt layer may produce liquefaction phenomenon,sand liquefaction will further cause uneven settlement of the foundation and track section,and even threaten the safety of train operation.At the same time,with the increase of operation time,it causes the accumulation of plastic deformation of the foundation,after the foundation deformation reaches the maximum design allowable,the tunnel foundation soil use function is reduced,easy to cause large settlement.In addition,when the train is running in the curve section of the tunnel due to its outer track super high design makes it easier to produce larger uneven settlement compared to the straight section.Combined with the above factors,there are great potential risks for the safe operation of trains under adverse geological conditions in curved sections.Such problems have been encountered in curved sections in different cities at home and abroad,so it is important to study the dynamic response of the soil around the tunnel and the long-term settlement pattern of the tunnel caused by the vibration load of the train in curved sections.In this paper,the tunnel settlement of a subway shield section in a city is the influence of the influence of the train vibration load on the deformation response law of the soil layer around the curve tunnel and the long-term settlement through the combination of numerical simulation and theoretical calculation.In this paper,studies were conducted on:(1)Post-work field monitoring of the soil around the shield tunnel under vibratory train loads in a curved section in a silt layer to study the pore water pressure in the foundation soil,changes in groundwater level and the development of long-term tunnel settlement.(2)The three-dimensional numerical model of soil-tunnel-tunnel coupling,analyzes the deformation response law of the shield tunnel and the surrounding soil,and compares the numerical simulation results with the field measurement results to prove the reliability of the numerical model.(3)A method of calculating the long-term settlement of foundation soil under the vibration load by combining experience and finite element method is proposed to study the deformation response law and the law of the shield tunnel under different working conditions. |
