Physical and Numerical Modeling of Micropile Group Slope Protection Bearing Test

ABSTRACT In order to study the force characteristics and reinforcement mechanisms of the bank protection capacity of micropile groups under rain seepage, two different scale models were employed using model tests and the finite element method. Focusing on the stress within the micro-piles, the lateral soil pressure against the piles, the displacement at the pile tops, and the overall stability of the embankment reinforced by the micro-piles, engineers can assess the performance and durability of the structure during rainwater scouring. The study shows that rainfall leads to increased soil saturation, which in turn reduces the soil’s shear strength. When subjected to loading after rain, micropiles within the same row exhibit similar strains. The thrust from potential landslides at the top of the slope causes the rear row of piles to experience greater flexural deformation. The difference between the soil pressure values of the same row after rainwater infiltration is small, and the overall soil pressure value increases in a stepwise manner with the increase of loading volume. The micropile support helps reduce soil displacement. The displacement of the middle and front row of piles is significantly lower compared with the back row by 32.3 % and 35.7 %, respectively. The pile group can limit the soil displacement within a certain range, which is beneficial for improving the stability of bank slopes under rainfall scouring. The micropile group enhances the overall slip resistance of the bank slope and can inhibit the development of the slip and crack surface of the bank slope to a certain extent. In engineering design, it is crucial to determine an appropriate pile spacing. A too small spacing can prevent the piles from achieving their optimal bending strength, whereas too large a spacing may lead to the risk of the bank slope as a whole experiencing overturning damage.