Abstract In order to study deformation behaviors of the enclosure structure of the foundation pit in Nanjing soft soil area, this paper discusses the deformation causes of the enclosure structure of the foundation pit by analyzing field measured data of an extra-long special-shaped deep foundation pit in Nanjing. The results show that the lateral displacement patterns of the diaphragm walls are all in shape of a convex drum towards the foundation pit, and there are little differences between reinforced concrete bracing and steel bracing in terms of controlling the diaphragm wall deformation. The maximum lateral displacement of diaphragm wall is less than 1% of the excavation depth and generally occurs between 4 m below the excavation point and the vicinity of the excavation point. The dimensionless maximum lateral displacement of diaphragm wall decreases with the increase of the thickness of soft soil above the wall bottom, and the dimensionless depth of maximum lateral displacement of diaphragm wall increases slightly with the increase of the thickness of soft soil above the wall bottom. Compared with other foundation pit data,the heaving resistance coefficient of the foundation pit bottom is higher, and the maximum lateral displacement of diaphragm wall is also smaller in the studied case. The insertion ratio of diaphragm wall and the horizontal bracing spacing are less relevant to the diaphragm wall deformation.
Abstract：
In order to study deformation behaviors of the enclosure structure of the foundation pit in Nanjing soft soil area, this paper discusses the deformation causes of the enclosure structure of the foundation pit by analyzing field measured data of an extra-long special-shaped deep foundation pit in Nanjing. The results show that the lateral displacement patterns of the diaphragm walls are all in shape of a convex drum towards the foundation pit, and there are little differences between reinforced concrete bracing and steel bracing in terms of controlling the diaphragm wall deformation. The maximum lateral displacement of diaphragm wall is less than 1% of the excavation depth and generally occurs between 4 m below the excavation point and the vicinity of the excavation point. The dimensionless maximum lateral displacement of diaphragm wall decreases with the increase of the thickness of soft soil above the wall bottom, and the dimensionless depth of maximum lateral displacement of diaphragm wall increases slightly with the increase of the thickness of soft soil above the wall bottom. Compared with other foundation pit data,the heaving resistance coefficient of the foundation pit bottom is higher, and the maximum lateral displacement of diaphragm wall is also smaller in the studied case. The insertion ratio of diaphragm wall and the horizontal bracing spacing are less relevant to the diaphragm wall deformation.
GU Zhenxue1 LOU Weizhong2 CHENG Yubo1 LI Yiwei1 SONG Dewei1 SUN Yang1
.Analysis on Deformation Behaviors of Diaphragm Walls of an Extra-long Special-shaped Deep Foundation Pit in Nanjing Soft Soil Area[J] MODERN TUNNELLING TECHNOLOGY, 2021,V58(1): 182-189
2021, Vol. 58 