|Table of Contents|

Experimental study on influence of deep foundation pit excavation and inner support adjustment on adjacent open caisson(PDF)

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

Issue:
2023年05期
Page:
174-182
Research Field:
岩土工程
Publishing date:

Info

Title:
Experimental study on influence of deep foundation pit excavation and inner support adjustment on adjacent open caisson
Author(s):
DENG Bin1;  ZHANG Lei2;  ZHENG Pengpeng1;  CHEN Baoguo2;  ZOU Shunqing1
(1. Sinohydro Bureau 7 Co., Ltd, Chengdu 610081, Sichuan, China; 2. Faculty of Engineering, China University of Geosciences(Wuhan), Wuhan 430074, Hubei, China)
Keywords:
deep foundation pit;  open caisson;  adjustable inner support;  stress characteristic;  model test
PACS:
TU470
DOI:
10.19815/j.jace.2022.01034
Abstract:
In order to investigate the variation law of the stress characteristics of the foundation pit and the adjacent open caisson under the excavation of the foundation pit and the adjustment of the inner support, indoor model tests of foundation pit-open caisson were carried out to analyze the change law of the soil pressure on the sidewall of the open caisson, the internal force, the settlement of the surrounding surface, and the lateral earth pressure on the diaphragm wall back. The results show that the lateral earth pressure on the diaphragm wall back decreases, the horizontal bending moment of the sidewall of the open caisson changes from positive to negative, the position of the maximum bending moment gradually moves down with the increase of the excavation depth, and the surrounding surface settlement is triangularly distributed during the excavation of the foundation pit. When adjusting the expansion and contraction of the inner support, the soil pressure behind the diaphragm wall near the current support depth is most obviously affected, and the change rate of the local soil pressure is highest when the third support is adjusted, and the local soil pressure value reaches the maximum when the fourth support is adjusted. The combined effect of simultaneous adjustment of multiple supports is greater than that of single support adjustment. Inner support adjustment may cause the open caisson to rotate to a certain extent, and the effect on soil pressure at the sidewall of the open caisson near the foundation pit is greater than that on the opposite side. The extension of the inner support can reduce the displacement of the foundation pit enclosure and the adjacent open caisson to a certain extent, but it will lead to a sharp increase in the local bending moment and earth pressure of the open caisson, so the field monitoring of earth pressure and structural deformation should be increased in the project.

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Last Update: 2023-09-01