Impacts of deep open excavation on the adjacent buildings in urban areas

THANG, Chu Duc, Ir. Dwikorita Karnawati, M.Sc., Ph.D

2009 | Tesis | S2 Teknik Geologi

Gedung City Theatre adalah salah satu stasiun bawah tanah yang dibangun menggunakan metode penggalian terbuka di sistem stasiun bawah tanah Hochiminh City. Mengelilingi lokasi penggalian City Theatre, terdapat dua bangunan yang dapat rusak di tengah-tengah proses penggalian yaitu gedung LV dan gedung ST. Tujuan penelitian ini adalah memperkirakan perubahan bentuk bangunan gedung LV dan ST dan perubahan bentuk tiang pondasinya karena penggalian City Theater Station. Di dalam thesis ini, pendekatan unsur empiris dan terbatas digunakan dalam menganalisa dampak pelaksanaan penggalian terhadap dua bangunan tersebut. PLAXIS 2D versi 8.6 digunakan dalam pendekatan unsur terbatas. Hasil analisis menujukkan bahwa berjadi perubahan bentuk yang serius pada gedung LV dan gedung ST karena penggalian City Theater Station, terutama pada gedung LV. Penururan ketinggian tanah maksimum pada gedung LV dan gedung ST sebanyak 55m dan 44mm berdasarkan pendekatan unsur empiris, serta 55mm dan 53mm berdasarkan pendekatan unsur terbatas. Golongan kerusakan gedunggedung tersebut berkisar antara 2 sampai 4. Selanjutnya, terdapat banyak tiang pondasi pada gedung LV dan ST yang mengalami keretakan selama penggalian. Jadi, sebelum dilakukan penggalian City Theater Station perlu dilakukan langkahlangkah perlindungan terhadap gedung LV dan ST. Faktor-faktor utama yang mempengaruhi kerusakan gedung antara lain jarak antara tiang pondasi dengan sekat dinding, jarak antara tiang dengan sudut penggalian stasiun, berat gedung, dan kekakuan sekat dinding, yang menopang kekakuan gedung.

City Theater is one of underground station of the underground urban railway system of Ho Chi Minh City, Viet Nam that is constructed by open excavation method. Surrounding the City Theater Station excavation there are two buildings LV and ST that can be damaged during the excavation. The objectives of research are predicting the deformation of building frame of building LV and building ST as well as the deformation of their pile foundation due to City Theater Station excavation. In this thesis, the empirical and finite element approaches are two methods that are used for predicting the impacts of City Theater Station excavation process to building LV and building ST. PLAXIS 2D version 8.6 is used for finite element approach. The results of analysis show that the deformation of building LV and building ST due to City Theater Station excavation are serious, especially building LV. Maximum vertical settlement of building LV and ST is 55mm and 44mm based on empirical analysis, 58mm and 53mm based on finite element analysis, respectively. The damage category of these buildings is range from 2 to 4. Furthermore, there are many pile foundations of building LV and Building ST can be occurred cracks during the excavation. Thus, before excavating the City Theater Station excavation, some protective measures have to be implemented to building LV and building ST. The main factors that controlling the damage of the buildings are the distance of pile foundation to diaphragm wall, the distance of pile to the corner of excavation, weight of building and stiffness of diaphragm wall, strut as well as stiffness of the buildings.

Kata Kunci : Penggalian terbuka,Gedung yang berdekatan,Pendekatan unsur empiris,Pendekatan unsur terbatas,Golongan kerusakan,open excavation, adjacent building, empirical approach, finite element method, damage category.