列车荷载下桩网结构地基可靠度及变形影响分析OA

The action mechanisms of train load and the pile-net structure foundation are relatively complex,but there is relatively little research on the overall stability analysis of pile-net structure foundations based on reliability theory.To accurately evaluate the stability of high-speed railway foundations,a typical cross-section of the Harbin-Dalian high-speed railway was selected as the research subject.The equivalent normalization method was employed to calculate the reliability index and failure probability of the pile-net structure foundation.Additionally,numerical simulations of the settlement deformation of the pile-net structure foundation were conducted using FLAC3D to further explore the influence of different factors on foundation settlement,aiming to reveal the impact of key factors such as train speed,pile spacing,and pile length on foundation reliability and settlement deformation.The research results indicated that as the train speed increased from 160 km/h to 300 km/h,the failure probability of the pile-net structure foundation increased by 0.0017%,indicating that the increase in train speed had a negative impact on foundation stability,which needed to be considered in the design.On the other hand,when the pile spacing increased from 1.5 m to 2.2 m,the failure probability increased by 3.56%,a value much greater than the effect of train speed on failure probability,indicating that pile spacing was a crucial factor affecting foundation reliability.When the pile length increased from 25 m to 26 m,the failure probability of the pile-net structure foundation decreased by 0.0038%,showing that appropriately increasing pile length could enhance foundation reliability,but its effect was relatively small.In terms of settlement deformation,as train speed,pile spacing,and pile length increased,the settlement deformation of the subgrade top surface directly beneath the track slab reached the maximum value,while the settlement deformation at the subgrade edges approached zero,indicating that the train load was primarily concentrated directly beneath the track slab,and the settlement at the subgrade edges had a small impact on overall stability.Comparing the effects of train speed and pile spacing on settlement deformation,it was found that the influence of pile spacing was also the most significant.Therefore,in optimizing foundation design,priority should be given to pile spacing to enhance overall foundation stability and resistance to settlement deformation.