摘要(英) |
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. |
參考文獻 |
1. Bowles J. E., Foundation Analysis and Design., McGraw-Hill, Singapore, pp. 313-316, (1997).
2. Clough G. W. and O’Rourke T. D., “Construction Induced Movements of In-situ Walls.” Proceeding, Design and Performance of Earth Retaining Structure, ASCE Special Conference, No. 25, pp. 439-470, (1990).
3. Clough G. W. and Hansen L. A., “Clay Anisotropy and Braced Wall Behavior.” Journal of the Geotechnical Engineering Division, ASCE, Vol.107, No. 7, pp.893-913, (1981).
4. Hsieh P. G. and Ou C. Y., “Shape of Ground Surface Settlement Profiles Casued by Excavation.” Canadian Geotechnical Journal, Vol.35, No.6, pp. 1004-1017, (1998).
5. Masuda T., Einstein H. H. and Mitachi T., “Prediction of Lateral Deflection of Diaphragm Wall in Deep Excavation. ”Journal of Geotechnical Engineering, No. 505, pp. 19-29, (1994).
6. Mana A. I. and Clough G.W. “Prediction of Movements for Braced Cut in Clay.” Journal of Geotechnical Engineering Division, ASCE, Vol.107, No.7, pp. 759-777, (1981).
7. Mesri, G., “A re-evaluation of Su(mob)≈0.22σp using laboratory shear tests, ”Canadian Geotechnical Journal, Vol. 26, No.1, pp. 162-164.
8. Ou C. Y., Hsieh P. G. and Chiou D. C., “Characteristics of Ground Surface Settlement During Excavation.” Canadian Geotechnical Journal, Vol.35, pp. 758-767, (1993).
9. Terzaghi, K, Theoretocal Soil Mechanics, Wiley, New York, (1943).
10. Woo S. M. and Moh Z. C., “Geotechnical Characteristics of Soils in Taipei Basin.” Proceedings, 10th Southeast Asian Geotechnical Conference, Vol.2, pp. 51-65, (1990).
11. 中華民國內政部營建署,「建築技術規則」,2014。
12. 吳沛軫、王明俊、彭嚴儒,「連續壁變形行為探討」,第七屆大地工程學術研究討論會,台北金山,第601-608頁(1997)。
13. 歐章煜,進階深開挖工程分析與設計,科技圖書,台北,2017。 |