Experimental study on inclined and vertical form retaining wall model and deformation control of soft soil foundation pit

The inclined and vertical form retaining wall (IVFRW) has become increasingly popular in foundation pit engineering, owing to its effective deformation control capabilities. However, soft soil may induce progressive deformation, requiring improved stabilization measures. A large-scale physical model test is designed for soft soil, encompassing five working conditions: conventional IVFRW (G1), cantilever retaining wall (G2), generally reinforced IVFRW (G3), IVFRW with added counterweighted concrete (G4), and IVFRW with prefabricated counterweighted concrete (G5). The experiment considers spatial and temporal effects on IVFRW performance. Concurrently, the efficacy of deformation control measures is validated. The test results show that the horizontal displacement of the pile top in G1, G3, G4, and G5 exhibits a reduction compared to G2. Notably, G4 demonstrates greater displacement control efficiency than G5 (at E4). All deformation time-history curves exhibited distinct rapid-development and stabilization phases, with G2 and vertical piles showing the most pronounced time-dependent effects. In addition, the incorporation of counterweighted concrete introduced a descending phase in curves, indicating reduced deformation. Applying counterweighted concrete at different pit depths effectively limits structural deformation while decreasing soil deformation. These findings can inform deformation control measures and engineering applications for IVFRW.