Evolution of active arching in granular materials: Insights from load, displacement, strain, and particle flow

The progressive failure of active soil arching in a quasi-static particle flow was investigated to elucidate the deformation behavior and load evolution mechanism. A transparent trapdoor test apparatus and self-developed particle image velocimetry system were used to capture the soil mass displacement field. Disturbed region and active region were introduced to characterize the displacement patterns evolution for both shallow and deep conditions. Meanwhile, the evolution of the surface settlement, horizontal displacement, and volumetric change of backfill as the trapdoor receding were quantified. The shear band propagation was interpreted considering the dilatancy behavior. In addition, the vorticity reveals local rotation characteristics in the shear region. Afterwards, i) the evolution mechanism of arching was speculated from macro-and microscopic perspectives. ii) The critical displacement for mobilizing the minimum load was discussed. These results can provide a profound understanding for mathematical modelling that is expected to illustrate the progressive development of active arching with displacement. [Display omitted] •Evolution of arching in a quasi-static particle flow were investigated.•Continuous deformation and strain were captured by self-developed PIV system.•Two different evolution of displacement patterns were identified.•Vorticity field distribution was basically consistent with that of shear band.•Evolution mechanism of arching in distinct stages were different and elucidated.