Numerical Study on Soil‐Arching Behavior in Pile‐Supported Embankments With Pile Settlement by Developed Damping Spring‐Based Trapdoor Model

Soil arching is one of the main mechanisms for load transfer in pile‐supported embankments, and the soil arching evolution patterns varied significantly depending on fill heights, pile spacings, pile stiffness, and soil stiffness. However, research on the effect of pile settlement on soil arching is relatively scarce, and most studies still use the traditional trapdoor test with a fixed arch foot to examine the soil arching. Therefore, this study establishes numerical models of a damping spring‐based trapdoor that considers pile settlement, and through 52 sets of spring‐based trapdoor tests and 1 set of reference tests, it systematically investigates the effects of various factors such as pile–soil stiffness ratio, fill height, and pile spacing on the soil arching under pile settlement conditions. The research results show that reducing the pile–soil stiffness ratio will reduce differential settlement between piles and soil, but it will exacerbate overall settlement. The stiffness ratio has a significant impact on soil arching: appropriately reducing the pile–soil stiffness ratio will help to recover fill deformation and suppress the formation of passive soil arch; increasing the stiffness ratio will enhance the stability of the soil arching. In addition, when the soft soil stiffness ks is low, pile settlement helps to enhance the soil arching, and the enhancement effect becomes more significant with an increase in fill height H and pile spacing S/a. When ks is high, pile settlement weakens the soil arching, which intensifies with an increase in fill height but weakens with an increase in S/a.