Working on Mega Infrastructure Projects and the Eurasia Tunnel Project – Ep 030

In this episode of The Geotechnical Engineering Podcast, we talk to Alp Gökalp, the deputy general manager of Kasktas Co. Inc., Istanbul, a leading specialized geotechnical contractor in Turkey about geotechnical applications and mega infrastructure projects in Turkey, and his involvement in the Eurasia Tunnel Project, an underwater tunnel between Asia and Europe. Engineering Quotes: Here Are Some of the Questions We Ask Alp Gökalp in This Episode: You are the deputy general manager of Kasktas Co. Inc. Tell us a bit more about the history and structure of your company and in which countries you have worked so far? What was the most challenging project in Turkey you've completed, and how did you overcome the difficulties of the proposed shoring system presented? You were involved in the Eurasia Tunnel Project, an underwater tunnel between Asia and Europe. Please could you tell us more about this project and your involvement in it? From a geotechnical point of view, what kind of challenges have you encountered in this project? You have completed a lot of mega infrastructure projects recently. How did you manage these challenging projects? Are there any special management tools/software or innovative approaches you have proposed and applied? What final advice can you give young engineers and geotechnical engineering students, especially those thinking of becoming geotechnical engineers? Here Are Some of the Key Points Discussed About Working on Mega Infrastructure Projects and the Eurasia Tunnel Project: The Osman Gazi Bridge was one of the most challenging mega infrastructure projects that Kasktas Co. Inc. has worked on. It is in a highly seismic area and is one of the highest bridges in the world. It involved using state-of-the-art geotechnical applications that were never used before in Turkey. The bridge is 2622 meters long with a 1550 meters long main span making it the sixth-longest span bridge in the world. When working on mega infrastructure projects in high seismic areas, the foundations need to be constructed far away from the fault line. It is difficult to do this for long structures such as tunnels, bridges, and pipelines. These structures need to cross the fault zones and deal with soft soils that are unstable and liquefiable. Unique and innovative design processes are needed for the foundations of these mega infrastructure projects. These design processes must be in line with the HSC quality control and insurance programs. The Eurasia Tunnel Project is a highway tunnel under the seabed that connects Asia and Europe. The tunnel is the sixth place in the world that has an excavation diameter of 13.7 meters and lies at 106 meters below sea level. It is the second place in the world to have high hydrostatic pressure of 11 bar resulting from the depth below sea level. It has a total length of 14.6 kilometers. The tunnel passes through complex geological structures, transition zones, and marine sediments in a highly seismic area. It is situated 17 kilometers away from the North Anatolian fault line. To decrease the seismic stresses and strains on the tunnel, two flexible seismic joints and segments were designed and applied in the tunnel. Mega infrastructure projects have many challenges that need overcoming. In projects like the Eurasia tunnel, to improve the weak ground by the shoreline and high groundwater pressure, a 30 meters deep impervious block was required to create a transition zone composed of 120-centimeter diameter unreinforced second bore piles. To increase the stability of the shoring system against high lateral pressures, a grid of underground support systems made of unreinforced diaphragm walls was constructed. To ensure mega infrastructure projects run as smoothly as possible, you need skilled technical and managerial staff,