Characterizing behavior of excavation-induced wall and ground movements with groundwater level and system stiffness

In this study, a design method using system stiffness influence factor (IF) was established to characterize the excavation-induced wall and ground movements with changes in groundwater level (GWL). The established factor for quantifying wall and ground behavior in this study considering GWL was regarded as an important aspect to prevent failures and ensure stable support systems design for the target structure. Irregular excavation configuration, common in urban areas, was considered using the three-dimensional finite element (FE) analysis, as well as different GWLs and various influence parameters for wall and support systems. Wall deflection and surface settlement were shown to decrease as the groundwater level was lowered and system stiffness was increased, especially with larger wall bending stiffness, higher wall embedment depth, and reduced vertical and horizontal strut spacings. These effects were particularly noted within re-entrant corner zones due to the corner stiffening effect. The influence of individual parameters was evaluated and quantified using the IF. A modification procedure for the IF was introduced to incorporate the effects of groundwater level, and the proposed method was shown to effectively predict wall deflection and ground settlement. Case example data confirmed the validity of this method, and its applicability in enhancing and optimizing excavation design was demonstrated. Overall, the proposed approach was offered as a practical and innovative framework for the design of excavation support systems under the influence of groundwater.