Willie Ang has over 20 years of public and private sector experience in the management and construction of tunnelling projects. He served as tunnel Manager for the Downtown Line and Thomson East Coast Line Mass Rapid Transit projects in Singapore. He began his career as a TBM operator/shift engineer and has managed various types of TBM including open face machine, earth pressure balance machine and slurry TBM in different ground conditions. He currently leads the overseas underground tunnelling tenders for Shanghai Tunnel Engineering Company for Asia Region, including project director for the Kai Tak Development – Stage 3B Infrastructure, Construction of Subway SW4 by Rectangular TBM. Mr Willie Ang holds a bachelor degree in civil engineering from Nanyang Technology University and is involved with the Building Control Authority Academy as an adjunct lecturer for its underground construction programme.

Today, it is well-recognized that underground structures are key to the sustainable development, especially in urban congested cities, improving living conditions with a lower impact on the environment.

With today’s advanced technologies, mechanised trenchless technology is often adopted as a method of construction over the traditional open-cut excavation methods or pipe roofing method and costs are kept economical, especially if the same machine is being reused in many projects. As a result, mechanised trenchless technology has been gaining popularity around the world.

The presentation provides an introduction of the rectangular Tunnel Boring Machine (TBM), the advantages and limitations of using this method of construction, and how the RTBM is the most suitable and urban landscape where space and time is critical for construction.

First developed and used in 1995 by Shanghai Tunnel Engineering Co. (STEC) in Mainland China, STEC has completed over 40 rectangular TBM projects in Mainland China. Since then, mechanized rectangular trenchless technology has undergone several stages of development, and it is now, for the first time in Hong Kong, going to be implemented in Kai Tak Development – Stage 3B Contract (Contract KT3B) for the construction of the underground pedestrian subway SW4.

The use of this method of construction, while unprecedented in Hong Kong, is aimed at increasing productivity in terms of time, quality and safety. Generally, the use of rectangular trenchless technology brings about similar benefits as that of the circular tunnel boring machines. Except that in the case of underground pedestrian subway construction, a rectangular machine would be ideal in bringing out the advantages of mechanized trenchless excavation without any compromise in its structural design or operational safety.

To further illustrate the feasibility and efficiency of using a rectangular TBM/pipe jacking machine for tunnel construction, the presentation also highlights some of the notable projects completed outside of Hong Kong.

In a nutshell, this presentation seeks to explain both tangible and non-tangible aspects of adopting rectangular trenchless technologies in underground construction.