Identifying failure connection area on wall for deep excavation based on system stiffness influence factor

• Published in: Engineering failure analysis 2024-10, Vol.164, p.108718, Article 108718
• Main Authors: Abbas, Qaisar, Yoon, Jonghyeog, Hahm, Kyungwon, Lee, Junhwan
• Format: Article
• Language: English
• Subjects: Excavation; Stiffness; Support system; Wall deflection; Weak connection
• ISSN: 1350-6307
• DOI: 10.1016/j.engfailanal.2024.108718

•Wall behavior of deep excavation with weak and defective strut-waler connection was investigated.•Various weak connection locations along the wall were considered and analyzed.•The effects of weak connection on wall behavior was characterized and quantified.•A method to identify failure connection area using system stiffness influence factor was established.•Case examples were selected to examine the validity of the proposed method. In this study, a methodology to identify weak or failure connection area on the wall of deep excavation was proposed based on the system stiffness influence factor (IF), which can be beneficially utilized for wall-collapse prevention and forecasting system. Irregular excavation configuration common in urban areas and various weak-connection locations were considered. Three-dimensional finite element analyses with full consideration of actual staged excavation and strut-waler connection condition were performed. It was found that wall deflection and ground movement increased as the location of weak connection became deeper. It was also found that the influence of weak connection on the wall behavior became more pronounced as it located towards the center of the wall. The effects of weak connection on wall deflection were evaluated and quantified using IF. A modification procedure for IF was introduced to consider the effects of depth and horizontal weak-connection locations. The modified IF was adopted to establish a method for quantifying and identifying weak or failure connection area on the wall based on measured wall deflection from field monitoring. Case examples were selected to check the validity of the proposed method. The compared results showed that monitored and predicted locations of weak connection were in close agreement.