• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.6
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• pp.985-997
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• 2017

In many countries, most of the tunneling works have been ordered by the shield TBM, and also Korean companies are actively bidding and execute in this project. In case of Korea, refurbished machines are mainly using in power cable, gas pipelines, and water and sewage tunnel. Also in metro projects, shield TBM of over diameter 7m is required mainly by using brand new machine. Since the shield TBM is not easy to change once it is produced, it is necessary for the client to provide sufficient information on the production conditions so as to satisfy various characteristics of the construction. In this study, to manufacturing optimal shield TBM, the Client's TBM requirements of tunnel construction in Hong Kong and UK was analyzed and compared with the domestic requirements. The results are expected to provide as client's guidelines for bidding stage and manufacturing for shield TBM tunneling in Korea in the future.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.5
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• pp.357-371
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• 2023

In cable tunnel construction using TBM, the vertical shaft is an essential structure for entrance and exit of TBM equipment and power lines. Since a shaft penetrates the ground vertically, it often encounters rock mass. Blasting or rock splitting methods, which are mainly used to the rock excavation, cause public complaints due to the noise, vibration and road occupation. Therefore, mechanical excavation using vertical shaft excavation machine are considered as an alternative to the conventional methods. However, at the current level of technology, the vertical excavation machine has limitation in its performance when applied for high strength rock with a compressive strength of more than 120 MPa. In this study, the potential utilization of waterjet technology as an excavation assistance method was investigated to improve mechanical excavation performance in the hard rock formations. Rock cutting experiments were conducted to verify the cutting performance of the abrasive waterjet. Based on the experimental result, it was found that ensuring excavation performance with respect to changing in ground conditions can be achieved by adjusting waterjet parameters such as standoff distance, traverse speed and water pressure. In addition, based on the relationship between excavation performance, uniaxial compressive strength and RQD, it was suggested that excavation performance could be improved by artificially creating joints using the abrasive waterjet. It is expected that these research results can be utilized as fundamental data for the introduction of vertical shaft excavation machines in the future.