Abstract Adopting Hardening-Soil finite element model based on soil unloading conditions, the influence of ex? ternal wall insertion ratio on deformation of retaining structure and soil was studied taking the foundation pit of a metro transfer station of Suzhou metro line 1 as background. The results show that the maximum lateral displacement of external wall decreases with an increase of insertion ratio within the range of 30-35 mm, and the lateral deformation at the foot of wall increases significantly in a linear form; the lateral deformation at the top of internal wall obviously increases linearly, while the maximum of lateral wall deformation of wall body increases slowly and there is almost no change at the bottom of wall; the uplift at the internal pit bottom is more than 90 mm and it is slightly effected by the insertion ration of external wall while the uplift at the external pit bottom is more than 70 mm and it increases with an decrease of the distance away from the external wall; soil mass settlement at the back of the external pit is obvious and it decreases with an increases of insertion ratio of external wall within the range 14 m away from the external wall, and the settlement reaches the maximum when the insertion ratio of external wall is 0.25 while the tendency of settlement develops reversely when the distance from the external wall is beyond 14 m. To en? sure the safety and reduce environmental impact, it is significant to determine a reasonable insertion ratio of external wall regarding the pit-in-pit excavation.
Abstract：
Adopting Hardening-Soil finite element model based on soil unloading conditions, the influence of ex? ternal wall insertion ratio on deformation of retaining structure and soil was studied taking the foundation pit of a metro transfer station of Suzhou metro line 1 as background. The results show that the maximum lateral displacement of external wall decreases with an increase of insertion ratio within the range of 30-35 mm, and the lateral deformation at the foot of wall increases significantly in a linear form; the lateral deformation at the top of internal wall obviously increases linearly, while the maximum of lateral wall deformation of wall body increases slowly and there is almost no change at the bottom of wall; the uplift at the internal pit bottom is more than 90 mm and it is slightly effected by the insertion ration of external wall while the uplift at the external pit bottom is more than 70 mm and it increases with an decrease of the distance away from the external wall; soil mass settlement at the back of the external pit is obvious and it decreases with an increases of insertion ratio of external wall within the range 14 m away from the external wall, and the settlement reaches the maximum when the insertion ratio of external wall is 0.25 while the tendency of settlement develops reversely when the distance from the external wall is beyond 14 m. To en? sure the safety and reduce environmental impact, it is significant to determine a reasonable insertion ratio of external wall regarding the pit-in-pit excavation.
.Sensitivity Analysis of the Influence of External Wall Insertion Ratio on Deformation of Pit-in-Pit[J] MODERN TUNNELLING TECHNOLOGY, 2018,V55(6): 87-93
2018, Vol. 55 