Investigation of the Axial Force Compensation and Deformation Control Effect of Servo Steel Struts in a Deep Foundation Pit Excavation in Soft Clay

Abstract

This study presents a comparative analysis of the deformation control effect of the hydraulic servo steel struts and ordinary steel struts of a foundation pit based on the measured axial force of the steel struts, lateral wall deflection, and ground surface settlement due to pit excavation. The results indicate that ordinary steel struts installed via axial preloading exhibit a disadvantageous axial force loss with a maximum value equal to 86.7% of the axial preloading force. When compared with ordinary steel struts, the hydraulic servo steel strut exhibits a superior supporting effect. The hydraulic servo steel strut adjusts the axial force in real time based on the deformation of the retaining structure and the axial force of the struts. Thus, the ratio of maximum lateral deflection to the excavation depth of a deep foundation pit in soft soil is less than 0.3%. Concrete struts undergo unsupported exposure during the excavation process, leading to sharply increasing deformation of the retaining structure. Therefore, regarding a foundation pit with strict requirements for deformation control, the use of hydraulic servo steel struts rather than concrete struts is recommended.

Deformation Control Monitoring of Basement Excavation at Field Construction Site: A Case of Hydraulic Servo Steel Enhancement Geotechnology

“…e deep excavation was numerically modelled to assess the effectiveness of hydraulic servo steel-supported excavation-induced deformation control, and their results were consistent with the determinations of Di et al [15] and Ye et al [20].…”

“…Steel bracing support stiffness enhanced by the hydraulic servo system has been reported by some researchers lately [15][16][17][18][19]. Specifically, Di et al [15] investigated the deformation control mechanism of steel bracing with servo support and steel bracing without servo support based on simulated measured data. ey divided the excavation pit into two parts.…”

Research on Deformation Law of Deep Foundation Pit of Station in Core Region of Saturated Soft Loess Based on Monitoring

“…In recent years, many scholars have analyzed the monitoring of different types of deep foundation pits in loess and soft soil areas. Clough, Long, Moormann C, and others carried out a classification study on the deformation of different foundation pits around the world and obtained the deformation law of foundation pits during construction [9][10][11]; Mei and Yang analyzed the deformation characteristics and influencing factors of foundation pits in Xi'an, Shanghai, Ningbo, Hangzhou, and other regions, respectively [12][13][14]; Zhou Yong, Ren Jianxi, Liu, Zhi, Li Zhe, Eibaz, and Wang Guohui studied and analyzed the monitoring data of pile displacement, surface settlement outside the pit, supporting axial force, and groundwater level during the excavation of the foundation pit [15][16][17][18][19][20][21]; Xu Jian and Zhang, respectively, compared numerical simulation and monitoring data of foundation pit excavation to analyze the deformation characteristics of foundation pit [22,23]; Zhang and Di studied the influence of the enclosure structure on ground settlement [24,25]; Farzi et al [26] conducted a systematic survey of the complex geotechnical characteristics of Ahwaz, and the displacement value during construction and excavation was checked and evaluated; Wang et al [27] analyzed the influence of soil structural changes on the horizontal displacement of the retaining structure wall, ground settlement, and adjacent subway tunnels during the excavation of the foundation pit; and Liu et al [28] analyzed the influence mechanism of rainfall on the deformation of the soft soil foundation pit support structure.…”

Study on Supporting Structure Performance of Deep Soft Soil Foundation Pit near Sea under Waves, Tides, Vibration, and Unbalanced Loads

“…From the existing research, researchers have drawn many conclusions about the influence of additional hydraulic loads such as waves and foundation pit construction loads on structure and soil in the coastal soft soil areas [18][19][20]. However, there are limited studies on the foundation pit in coastal areas under the simultaneous action of waves, tides, and vibration loads.…”