| 摘要: | 近年來台北地區因為地狹人稠關係，對於高樓與地下室需求與日俱增，都市深開
挖工程顯得尤為重要，但考慮到大台北地區主要地盤為軟弱的松山層，土層之間砂土
與軟弱黏土交錯，導致在進行深開挖工程中時常會碰到深厚軟弱黏土層，對於施工過
程得謹慎小心注意連續壁位移情況，必要造成施工區外有損鄰事件發生，對於工程師
是極大的挑戰。
而在民國112年9月7日晚間台北市中山區大直街發生深開挖施工破壞，此破壞
使連續壁壁體往開挖面內內擠造成壁體破壞，周遭鄰房也隨之發生大量沉陷與傾斜等
情況，而破壞原因有很多細節值得進行深入研究與討論。
本研究以 FLAC2D 模擬大直基泰工地的深開挖施工過程，蒐集地質、設計與施
工資料，依照實際施工順序，先設置地盤改良樁後，再設置連續壁與中間樁，來進行
基地開挖前的施工模擬，接續再進行四次開挖與三層支撐架設之後續施工模擬，直至
開挖至預定高程。後續變化連續壁貫入深度與厚度，支撐有無塑性鉸、地盤改良等因
素，探討其對深開挖破壞行為之影響。;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. |
