Summary Reader Response Draft #4

Tunnels in the past were utilized for purposes such as irrigation, drainage, and water transportation system as well as communication routes to improve the underground habitats to improve the standards of living. The Leonard (2022) webpage titled, “Innovation at the end of the tunnel”, informs readers about the rising need for underground infrastructures brought on by population pressure and urbanization. This underground infrastructure includes functions such as sanitation, logistics, and transportation. To meet these demands, modern tunnel-boring machines were introduced to meet these needs. As mentioned in another webpage by Trenchlesspedia, (2020, para. 2), tunnel-boring machines are referred to as “mole(s)” and are designed to bore circular tunnels through all types of earth, from sandy soil to hard rocks. The recently completed construction of the Thomson - East Coast Line (TEL) in Singapore is an excellent example of how this technology is being extensively utilized (Wong, 2019). Tunnels have traditionally been excavated through drilling and blasting, which uses explosives to break up rocks (Tunnel Boring Machine, 2023). Tunnel-boring machines (TBM), on the other hand, offer benefits such as rapid construction time and safe operations, which allows them to be widely used in underground space development and tunnelling projects (Gong, Yin, Ma, & Jian Zhao, 2016). In my opinion, modern tunnel-boring technology prevails over traditional tunnelling methodologies, such as drilling and blasting. This is because, despite its high initial cost, modern tunnel–boring technology is superior in terms of operational safety and building efficiency.

Modern tunnel-boring technology increases building efficiency by allowing for faster construction of building infrastructure. Land Transport Authority (LTA) project director Henry Foo stated that tunnel-boring machines save time, and manpower and are less disruptive (Tan, 2016).  LTA contends that the type of ground influences the speed of tunnelling. TBM can squeeze through 20 meters of marine clay in the same amount of time that it would take to cut through a 4-meter rock, which is approximately half the length of a bus. This process is being compared to "pushing toothpaste through a tube." (2022, para 6). This demonstrates that tunnel boring technology increases productivity and efficiency, allowing for faster infrastructure completion, which is ideal in construction projects. 

Another benefit of tunnel–boring technology is the ability for operational safety to take place during the construction of infrastructures. The utilization of TBMs increases safety by minimizing disturbances to the environment (IoT Innovation, 2022). The risk of workplace incidents, such as bodily injuries that can be minor or life-threatening, will be lowered for those working close to construction sites with minimizing disturbances.  Hence, increasing safety is essential to guarantee a construction site with zero accidents. In addition, when compared to conventional drilling and blasting methodologies, a TBM has the advantages of speed, efficiency, quality assurance, and high-level safety (Zhang et al., 2022). Before tunnel-boring can proceed, TBMs utilize accuracy and precision measurements. By doing this, it can create works of the highest caliber while achieving the greatest degree of accuracy, which increases reliability, boosts productivity, and enhances work quality—all of which are ideal at construction sites.  This shows that safety was prioritized while using the tunnel boring machine. Also, the tunnel-boring machines are secured by scaffolds and props while in use and are used in a regulated working environment, which suggests that tunnel-boring machine activities are safe.

Despite the many benefits of the TBM, it has its drawbacks – one of which is the high initial cost of tunnel boring technology. TBMs of today are larger in diameter, have more refined excavation technologies, and are more expensive than earlier generations of equipment. TBM is typically not economical for short tunnel runs due to the lengthy procurement and assembly time, coupled with the high initial cost of acquiring a machine, for tunnels that are less than a mile long (“Summary memorandum: tunnel construction study”, 2018, pg. 18, para. 4). Furthermore, if a specific excavation length is not obtained, the comparatively high initial cost of deploying the TBM results in poor economic feasibility (Kong, et al., 2021). In Singapore, the TBM construction method costs four times higher than cut -the and-cover method (Tan, 2016). Thus, this demonstrates that TBMs require more cost for this method to be used. However, TBMs are more cost-effective in the long run. New machines can recurrently excavate faster with less risk and surface settlement (Clark & Ramsey, 2017). Faster excavations reduce the duration of the tunnelling process. The time and manpower saved through quicker tunnelling would imply cost-savings for the project. Cost implications of operational risk and disturbance to the surface land are costly factors to consider in a project. Thus, reducing such risks would also suggest significant savings in the overall expense of the project. Hence, the long-term cost of a tunnelling project can be reduced as a result of lowered risks and shorter construction durations.

 

In conclusion, the advantages of using tunnel-boring technology make it a preferable choice for tunnel construction. The continuous use of TBMs in construction necessitates a recognition that technological improvement is essential to enabling these TBM machines to work more cost-effectively and efficiently. Therefore, for these machines to stay relevant and significant to the construction industry, more thorough research and modifications must be made.

 

Word Count: 865 Words

References:

Clark, G., & Ramsey, M. (2017, October 18). Tunnelingonline.com. https://tunnelingonline.com/advanced-technologies-help-overcome-tunneling-challenges-save-time-money/

Gong, Q., Yin, L., Ma, H., & Zhao, J. (2016). TBM tunnelling under adverse geological conditions: An overview. Tunnelling and Underground Space Technology, 57, 4-17. https://doi.org/10.1016/j.tust.2016.04.002

Kong, S., Choi, S., Shim, S., Lee, H., Oh, D., & Lee, S. (2021). Stability evaluation of TBM pilot tunnels to rear blasting using the protection shield. Applied Sciences, 11(4), 1759. https://doi.org/10.3390/app11041759

Leonard. (2022, January 26). Innovation at the end of the tunnel, by VINCI. https://leonard.vinci.com/en/innovation-at-the-end-of-the-tunnel/

Land Transport Authority. (2022, January 28). LTA. What lies beneath Meet LTA's digging machine. https://www.lta.gov.sg/content/ltagov/en/who_we_are/statistics_and_publications/Connect/TBMs.html

Mining Technology. (2023, January 5). IoT innovation: Leading companies in tunnel boring machines for the mining industry. https://www.mining-technology.com/data-insights/innovators-tunnel-boring-machines-mining-2/

MAPFRE Global Risks. (2019, May 7). Tunnel construction: Design for latest generation tunnel boring machines. https://www.mapfreglobalrisks.com/en/risks-insurance-management/article/tunnel-construction-rational-design-for-latest-generation-tunnel-boring-machines/

Tunnel boring machine (2021, April 6).  Engineering Channel. https://engineering-channel.com/tunnel-boring-machine/

Tan, C. (2016, June 15). New tunnel-boring machine makes cutting corners perfectly sound. The Straits Times. https://www.straitstimes.com/singapore/transport/new-tunnel-boring-machine-makes-cutting-corners-perfectly-sound

What is a tunnel boring machine (TBM)? - Definition from Trenchlesspedia. (2017, March 23). Trenchlesspedia - Trenchless Solutions Through Education. https://www.trenchlesspedia.com/definition/2572/tunnel-boring-machine-tbm

Wong, K. Y. (2019, November 23). Tunnelling for Thomson-East Coast line completed on schedule. The Straits Times. https://www.straitstimes.com/singapore/transport/tunnelling-for-thomson-east-coast-line-completed-on-schedule

 Zhang, Z., Wang, B., Wang, X., He, Y., Wang, H., & Zhao, S. (2022). Safety-risk assessment for TBM construction of hydraulic tunnel based on fuzzy evidence reasoning. Processes, 10(12), 2597. https://doi.org/10.3390/pr10122597