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Study on Excavation Time Sequence Optimization of Adjacent Deep and Shallow Foundation Pits in Jiangbei New District of Nanjing(PDF)

《建筑科学与工程学报》[ISSN:1673-2049/CN:61-1442/TU]

Issue:
2021年06期
Page:
108-118
Research Field:
Publishing date:

Info

Title:
Study on Excavation Time Sequence Optimization of Adjacent Deep and Shallow Foundation Pits in Jiangbei New District of Nanjing
Author(s):
TAO Yong1;  LYU Suo-zhang2;  YANG Ping1;  ZHANG Ting1;  WANG Xiao-mi2
(1. College of Civil Engineering, Nanjing Forestry University, Nanjing 210037, Jiangsu, China; 2. Jiangsu Jianke Engineering Consulting Co., Ltd., Nanjing 210008, Jiangsu, China)
Keywords:
adjacent foundation pit;  deformation law;  time sequence optimization;  numerical simulation
PACS:
TU470
DOI:
10.19815/j.jace.2021.09021
Abstract:
Based on the underground space foundation pit group project in Jiangbei New District of Nanjing, the numerical simulation study on the excavation of two adjacent foundation pits with large differences in depth and area was conducted, and three different excavation time sequences were proposed. The laws of retaining structure deformation, surface settlement and pit bottom uplift under different excavation time sequences were compared. The results show that the deformation of the outer wall of the foundation pit and the common wall are different under different time sequences. The depth and shallow alternate time sequence has the greatest control effect, followed by depth first and then shallow, and shallow first and then deep is the least. When excavating the lower part of the deep pit, the position of the maximum deformation of the common wall is near the bottom of the shallow pit under the time sequence of first shallow and then deep, while the position moves up to the top of the wall under the other two time sequences. In terms of surface subsidence outside the pit, the alternating sequence of depth and shallow has the greatest control effect, followed by depth first and then shallow, and shallow first and then deep is the least. During the construction of the upper part of the deep pit under the sequence of shallow first and then deep, the maximum settlement position is gradually close to the wall of the pit, and when the shallow pit is constructed under the sequence of deep first and then shallow, the position is far away from the wall. When the deep and shallow pits are constructed alternately, the position is also far away from the pit wall. When the soil under the deep pit is not excavated, the alternating depth and shallow sequence plays the most important role in controlling the bottom uplift of the shallow pit. When both the deep pit and the shallow pit are excavated, the time sequence of first shallow and then deep is most conducive to controlling the uplift of the deep pit bottom. Comparing the deformation laws of foundation pits in various time sequences, it is recommended to excavate such adjacent foundation pits in alternate depth and shallow time sequences.

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Last Update: 2021-11-01