| dc.description.abstract | Due to the limited land and dense population in the Taipei area in recent years, the
demand for high-rise buildings and basements has been increasing day by day, making deep
excavation projects in urban areas particularly important. However, considering that the
main stratum in the Greater Taipei area is the soft Songshan Formation, with layers of sand
and weak clay interlaced, deep excavation projects often encounter thick, soft clay layers.
This requires careful attention to the displacement of diaphragm walls during construction
to prevent damage outside the construction area, posing a significant challenge for engineers.
On the evening of September 7, 112th year of the Republic (2023), a deep excavation
construction failure occurred on Dazhi Street in the Zhongshan District of Taipei City. This
failure caused the diaphragm wall to squeeze inward toward the excavation face, resulting
in wall damage. The surrounding neighboring houses also experienced substantial
subsidence and tilting. There are many details of the cause of the destruction that are worth
in-depth research and discussion.
This study uses FLAC2D simulation to model the deep excavation construction process
at the Dazhi Ketai construction site. Geological, design, and construction data were collected,
and the actual construction sequence was followed. First, ground improvement piles were
set up, followed by the diaphragm wall and middle piles, to simulate the construction before
the excavation of the site. Subsequently, the simulation continued through four excavations
and the installation of three layers of support, until the excavation reached the predetermined
elevation.
The study explored the impact of variations in the penetration depth and thickness of
the diaphragm wall, the presence or absence of plastic hinges in the support, ground
improvement, and other factors on the behavior of deep excavation failure. | en_US |