| There are a large amount of deep silt soft soil in the coastal areas of southeastern my country.The groundwater level in the soft soil area is too high,resulting in high water content,and the soft soil makes it large in compression and slow in consolidation,which makes it difficult to meet the bearing capacity of the soft soil area for engineering construction.The pile foundation can make up for these shortcomings.Therefore,the super-long and large-diameter pile group foundation has become the main form of bridge foundation construction in soft soil areas.During the operation period,the long-term load effect of the vehicle,the weight of the embankment and the drop of the groundwater level will cause the soil to consolidate and settle,and the negative friction of the pile side caused by the pile will change the stress state of the pile foundation and even affect the normal use of the structure.Therefore,the research on the mechanical performance of bridge pile foundations in soft soil areas has practical engineering significance.The main research contents of this paper are as follows:(1)Summarize the important research results of the negative friction resistance of pile foundations at home and abroad in recent years,analyze the mechanism of the pile-soil system,and deeply study the reasons for the negative friction resistance of the pile side and its theoretical calculation methods and the theory of pile group settlement Calculation method.(2)Taking a coastal highway viaduct and road under the bridge as the engineering background,a reasonable constitutive model was selected,and the 3D finite element model of the 26# pier pile foundation was established using Midas/GTS NX finite element software,and the axis of the 26# pier pile foundation The force monitoring test data is compared with the numerical simulation results to verify the rationality of the numerical simulation;furthermore,different working conditions are drawn up on the road under the bridge with different conditions and different intervals on both sides of the fully loaded vehicle and one side of the empty side of the fully loaded vehicle,analysis and operation The impact of the road under the bridge on the change characteristics of the axial force of the pile and the side friction of the pile along the depth of the pile and the change law of the settlement of the pile under the action of the vehicle.(3)A three-dimensional consolidation finite element model of the 26# pier pile foundation of the road under the bridge under the combined action of the embankment weight and the vehicle load was established,and the changes in the time effect of the bridge pile foundation force during the operation period were analyzed in depth.In addition,the effect of water level changes was studied.The influence of the force characteristics of the pile foundation can be used to predict the change law of the pile foundation force during the operation period of similar projects with the operation time. |
