应用伺服钢支撑的超深盖挖逆作基坑变形分析OA

To clarify the application effect of the servo support system in top-down excavationreverse foundation pit and meet the requirements for refined design and construction of ultra-deep top-down excavation reverse foundation pit in soft soil areas,this study took Xiawafang Station of Tianjin Metro Line 8 as a case study.The deformation characteristics of an ultra-deep top-down excavation in soft soil supported by servo steel supports were investigated based on field monitoring data.The results show that the deep horizontal displacement of the diaphragm wall increases in stages with excavation depth,with a maximum horizontal displacement of approximately 40 mm.After the installation of servo steel supports,the average increment of deep horizontal displacement in the servo-controlled area is close to 0 mm,while the maximum increment in the passive support area of the standard section reaches about 15 mm,indicating that servo steel supports can effectively restrain the deformation of the diaphragm wall and reduce the deformation differences along the excavation.The vertical displacement of the wall is significantly influenced by the construction sequence,and the uplift of the earlier excavated area is about 30%～40%larger than that of the later excavated area.The maximum ground surface settlement around the excavation is about 25 mm,which is approximately 0.6 times the maximum horizontal displacement of the diaphragm wall.The maximum settlement occurs at a distance of 5～15 m from the edge of the excavation.The results provide data support for the design and construction of servo support systems in ultra-deep top-down excavations in soft soil areas.