Cantilever steel tubular pile wall embedded in soft rock subjected to sequential loadings

A centrifuge model is developed to simulate sequential dynamic and static loadings with clear boundary conditions, aiming to comprehend the mechanical response of a cantilever-type retaining wall embedded into the soft rock. The model wall was made of steel tubular piles with a 2 m diameter and 25 mm thickness in a prototype scale under 50g. Wall retained height (H) and embedment depth (d_r) into model soft rock (q_u = 1.4 MPa) were 12 and 3 m, respectively. Sequential loadings (dynamic and static) were applied to the wall with dry and saturated backfill sand. It was found that the resilience of the wall created by the confinement of soft rock during the dynamic loading is a critical factor that controls the earth pressure and the dynamic and residual displacements of the wall, both during and after the dynamic loading and the static loading. Due to the resilience effect, an effective earth pressure ratio of more than the design active or even an at-rest pressure coefficient could be expected, especially after dynamic loading. However, a slight wall movement in the static loading and wall creep displacement after dynamic loading could reduce this resilience effect.