关键词: 超深基坑, 双道地下连续墙, 降水, 围护变形

Abstract: The rapid development of cities has made the surface construction space increasingly limited, and the requirements for the development and construction of underground space are gradually increasing. Dewatering is a necessary measure to ensure the smooth excavation of foundation pits, and it is also an important reason for the deformation of retaining structures. Based on the deep foundation pit of Suzhou River’s deep drainage and storage pipeline in Shanghai, the deformation characteristics of the dewatering in the “double water-resisting system” of double diaphragm walls were analyzed. The results showed that the diaphragm wall showed a “bulge-shaped” deformation towards the foundation pit with the excavation and dewatering, and local displacement peaks appeared within the depth range of the filter pipe in the well. The depth of maximum displacement was mostly concentrated in the range of 55-66m, and the maximum displacement was only 7.9mm. The vertical displacement of the surface at the edge of the pit showed a decreasing trend away from the foundation pit and stabilized at about 30 meters. The surface within 10 meters of the edge of the foundation pit was in a raised state. The peak displacement of the second diaphragm wall was within the depth range of 8-24m, and the deformation was less directly affected by the dewatering in the pit.

Key words: Large Deep Excavation, Double Diaphragm Wall, Dewatering, Wall Deflection