Abstract
The Dongjiekou Station of the Fuzhou Urban Rail Transit Line 4 Phase I Project is located in the city center area, constituting a three-level underground station featuring a cross interchange with Line 1. The surrounding environment is complex, with certain foundation pit retaining structures positioned in immediate proximity to existing buildings. Specifically, the diaphragm wall on the south side of the west section was constructed by the adjacent shopping mall and is situated directly beneath the basement slab of the mall at a depth of approximately 6 m. During the foundation pit excavation process, water leakage was identified in the retaining structure completed by the adjacent mall. Through a combined construction technique encompassing pre-grouting sealing from the interior side of the leakage points, pre-grouting sealing via drilled holes from the exterior side beneath the existing building, and steel plate sealing during excavation, the leakage points were successfully sealed, thereby ensuring the safety of both foundation pit excavation and structural construction. This article elaborates on the treatment methodology for water leakage in foundation pit retaining structures immediately adjacent to existing buildings, drawing upon the case study of diaphragm wall leakage treatment at the Dongjiekou Station foundation pit of the Fuzhou Urban Rail Transit Line 4, thereby providing a valuable reference for similar engineering projects under analogous working conditions.
Full Text
Introduction to Treatment Techniques for Water Seepage in Foundation Pit Retaining Structures Underneath Existing Buildings
Chen Ruiheng
Shanghai Tunnel Engineering Co., Ltd., Shanghai 200000, China
Abstract
Dongjiekou Station of Fuzhou Metro Line 4 Phase I is located in the city center, serving as a three-level underground station that forms a cross interchange with Line 1. The surrounding environment is complex, with some foundation pit retaining structures constructed immediately adjacent to existing buildings. In particular, the diaphragm wall on the south side of the western section was constructed by a neighboring shopping mall as part of its development and is situated directly beneath the mall's basement slab at a depth of approximately 6 m.
During excavation, water seepage was discovered in the retaining structure constructed by the adjacent shopping mall. A combined construction technique was employed to seal the leaks: pre-sealing through grouting on the interior side of the leakage points, pre-sealing through drilled-hole grouting on the exterior side beneath the existing building, and steel plate sealing during excavation. This approach successfully sealed the leakage points and ensured the safety of both excavation and structural construction.
This paper presents a case study of water seepage treatment in the diaphragm wall at the interface between the Dongjiekou Station foundation pit and an adjacent building in Fuzhou Metro Line 4. It elaborates on the treatment techniques for water seepage in foundation pit retaining structures immediately adjacent to existing buildings, providing a reference for similar engineering projects.
Keywords: existing buildings; retaining structures; water seepage; grouting; leak sealing; anti-blowout device