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Numerical simulation of tunnel excavation under thin rock cover

Numerical simulation of tunnel excavation under thin rock cover / Linda Tan Lee Zhi
Pahang-Selangor Raw Water Transfer Tunnel merupakan salah satu terowong panjang yang akan melalui pelbagai keadaan geologi dan topografi. Pembinaan terowong tersebut adalah satu tugasan yang amat mencabar. Ini adalah disebabkan terdapat banyak faktor-faktor yang tidak dapat diamalkan sepanjang pembinaan dijalankan. Dalam kajian ini, lokasi pembinaan terowong terletak di tempat yang cetak dan bawah sungai. Oleh itu, ciri-ciri terowong adalah sangat penting dan harus difahami supaya terowong adalah mampan dan selamat. Dengan menggunakan kaedah ―Inverse Distance Weighting‖, profil subpermukaan sepanjang terowong dapat dihasilkan. Selepas itu, profil litologi dan jisim batu luluhawa bergred boleh dijana dari profil subpermukaan. Berdasarkan analisis profil jisim batu luluhawa bergred, batu-batu jisim yang terdapat sepanjang terowong adalah batu gred II dan III. Selepas itu, satu model terowong akan dihasilakn dan digunakan untuk menguji anjakan maksimum yang akan dicapai dengan kaedah ―Finite Element Method‖. Kajian ini adalah berdasarkan beberapa andaian seperti jisim batu adalah plastic dan perantara yang homogen. Selain itu, andain yang lain termasuk terowong dihasilkan dengan menggunakan kaedah ―New Austrian Tunneling Method (NATM)‖. Anjakan maksimum akan dibanding melalui dua situasi iaitu dengan sistem penyokongan dan tanpa sistem penyokongan dengan kaedah graf. Sistem penyokongan yang dicadangkan adalah seperti forepoling, keluli rusuk, bolt batu dan shotcrete. Hasil selepas analisis menunjukkan anjakan maksimum yang mempunyai sistem penyokongan adalah rendah daripada terowong tanpa sistem penyokongan. Dengan ini, kefahaman tentang penggunaan sistem peyokongan dan tanpa sistem penyokongan terhadap terowong adalah penting supaya dapat membina terowong yang selamat dan mampan. _______________________________________________________________________________________________________ Pahang-Selangor Raw Water Transfer tunnel is a long tunnel where it will pass through various topographical and geological conditions. It is a challenging task to construct a long tunnel as there are too many uncertainties involved during construction, especially tunnel passing through a shallow overburden area. Thus, engineering properties that controls the behavior of shallow tunnel should be indentified and understanding for the sustainable design of the tunnel. In this study, a subsurface profile along the shallow tunnel alignment is developed based on the input of engineering properties data using Inverse Distance Weighting method. From the developed subsurface profile, the evaluation is done according to the lithology profile and rock mass weathering grade profile. From the analysis, the rock mass weathering grade along tunnel alignment are mainly in rock grade II and III. A conceptual model is then developed based on the data obtained from the evaluation. The behavior of the surrounding rock is evaluated based on the maximum displacement using Finite Element Method. This study is carried out by assuming the rock mass as a plastic and homogeneous medium and the tunnel was excavated using the New Austrian Tunneling Method (NATM). Countermeasures such as forepoling, steel rib, rock bolt and shotcrete were used to observe the changes in tunnel behaviors between tunnel excavation with and without support system. Finally the relationship between the maximum displacement with and without countermeasures was plotted into graphs. Results showed that the displacement of tunnel with supports is lower compared to the tunnel without adopting support. Thus, it is important to understand the shallow tunnel behaviors between without and with tunnel support system in order to allow engineer to make better preparation or mitigations to overcome the unfavorable conditions that will occur during the tunnel construction.
Contributor(s):
Linda Tan Lee Zhi - Author
Primary Item Type:
Final Year Project
Identifiers:
Accession Number : 875000578
Language:
English
Subject Keywords:
tunnel; construction; overburden
First presented to the public:
5/1/2014
Original Publication Date:
12/26/2019
Previously Published By:
Universiti Sains Malaysia
Place Of Publication:
School of Civil Engineering
Citation:
Extents:
Number of Pages - 108
License Grantor / Date Granted:
  / ( View License )
Date Deposited
2020-01-06 17:33:14.108
Submitter:
Mohd Jasnizam Mohd Salleh

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