关键词: 超深地连墙, 槽壁侧压力, 现场监测, 数值分析, 施工扰动

Abstract: The detailed analysis of disturbance induced by diaphragm wall construction plays an important role in predicting the environmental influence of deep excavations, especially the super-deep excavation. Therefore, this paper collected and analyzed the field data of slurry pressure and concrete pressure during the construction of a 102 m super-deep diaphragm wall. The evolution law and vertical distribution mode of the lateral pressure on the trench wall during the construction were summarized, followed by a new proposed tri-line model of lateral pressure on the trench wall and its validation. The proposed tri-line model can well capture the first increase and then decrease trend of the lateral pressure on the trench, and it can return to the classic bi-line model. Finally, the fine numerical simulation of the construction process of a 102 m diaphragm wall, including the trenching and concreting, was performed adopting both the tri-line model and bi-line model. The stress state and deformation of soils around the trench were analyzed and compared. The results revealed that the construction of super-deep diaphragm walls can lead to the stress redistribution of adjacent soil. The effect zone is about 1.6D (D is the panel length) along the panel direction and about 4.3D perpendicular to the panel. The stress redistribution is controlled by vertical and horizontal transfer mechanisms, and the horizontal transfer mechanism dominates. In Shanghai soft soil area, the concreting would compress the trench wall and increase the trench volume, causing the increase of concrete volume.

Key words: super-deep diaphragm wall, lateral pressure on the trench, field monitoring, numerical simulation, construction disturbance