Sofia Metro Line 3: Lot 4 Advances Urban Rail Infrastructure

Sofia Metro Line 3: Lot 4 Excavation Completed, Advancing Urban Mobility

The DVU21 Joint Venture, led by Doğuş İnşaat, has reached a significant milestone in the expansion of Sofia’s metro network. The team has successfully completed excavation works for Lot 4 of Line 3, culminating in the breakthrough to the first station. This achievement, announced earlier this week, marks a crucial step in a project designed to alleviate traffic congestion and enhance the city’s public transportation infrastructure. This article explores the progress of Lot 4, providing context on the larger Line 3 project and its projected impact on Sofia’s urban environment. The completion of the excavation phase underscores the ongoing commitment to improve public transport in Sofia. The project involves the extension of the current Sofia Metro, Line III Lot 4 in relation to Depot “Botevgradsko Shosse” Boulevard – VI. Vazov Boulevard, Central City Area, “Ovcha Kupel” District – Lot 4: km 11+966,34 (Start Shaft) – km 5+248,57 (Exit Shaft) Construction of TBM Tunnel.

Lot 4: A Detailed Overview

Lot 4, also known as the Slatina section, is a 5.4 km underground segment of Line 3. This section will run from Shipka Street and the Slatina District towards Tsarigradsko Street. The Metropoliten EAD project involves a 5.67 km section featuring six stations, with the aim of significantly reducing urban vehicle traffic by an estimated 30% and raising the rail system’s share in public transport to 50%. Construction is progressing using a Tunnel Boring Machine (TBM) method. The TBM tunneling works are scheduled to conclude in Q4 2026, with the line’s projected operational launch in April 2027. Doğuş İnşaat reports that it has completed 25% of the work on this line. As the lead contractor, Doğuş İnşaat has built 90% of all TBM-built metro tunnels in Sofia, contributing significantly to the city’s underground rail network.

The Broader Scope of Sofia Metro Line 3

Sofia Metro Line 3 will span a total of 21 km, incorporating 21 stations and branches. The entire project is planned to be constructed in four distinct stages or lots, due to its large-scale requirements, the different construction methods involved, and financial constraints. The initial stage, which was completed from 2016 to 2020, included a 7.8 km stretch with eight stations, as well as a depot near Zhitnitsa. The second stage included 4 stations, and the third, a 3 km section with three stations. The fourth lot, which is Lot 4 currently under construction, begins at the entrance of the Military Academy at Evlogi and Hristo Georgievi Blvd. It progresses through Geo Milev RD, Slatina RD, and along Arena Armeets to Tsarigradsko Shose Blvd. Upon completion, the entire Line 3 network aims to provide comprehensive coverage across Sofia.

Construction Methodology and Technological Advancements

The project utilizes advanced TBM technology for tunnel construction, which is critical for navigating the varied geological conditions and urban density. The use of TBMs minimizes surface disruption compared to traditional cut-and-cover methods, vital for minimizing the impact on Sofia’s residents and businesses. The construction of tunnels under existing urban infrastructure poses significant engineering challenges that require precision and expertise. The project also employs sophisticated monitoring systems to manage ground movement, ensuring the safety and stability of existing buildings. These techniques enable the rapid and efficient completion of the tunnel sections, facilitating the implementation of future rail infrastructure.

Conclusion

The completion of the excavation phase for Lot 4 of Sofia Metro Line 3 by the DVU21 Joint Venture, represents a major milestone in Sofia’s efforts to modernize its public transport system. The advancements in TBM technology, coupled with the strategic approach of phased construction, demonstrates the capability to deliver complex urban infrastructure projects effectively. Once the entire Line 3 project is finished, the citizens of Sofia can expect to see a significant reduction in traffic congestion and a boost to the city’s overall transportation efficiency. The success of this project will act as a benchmark for future public transportation projects in Bulgaria and within the broader European context. This project also demonstrates how collaboration between experienced construction companies and municipal authorities can transform urban transportation landscapes, creating sustainable and efficient city environments.

Company Summary

Doğuş İnşaat, as the leader of the DVU21 Joint Venture, is a major player in the global construction sector. The company specializes in large-scale infrastructure projects, including railways, tunnels, and urban transport systems. Doğuş İnşaat has built 90% of all TBM-built metro tunnels in Sofia, highlighting its expertise and experience in executing technically demanding projects within complex urban environments. Their proven track record demonstrates a commitment to innovation, quality, and the successful delivery of railway infrastructure projects. The company’s involvement in the Sofia Metro project further solidifies its position as a key contributor to the advancement of railway infrastructure in Europe.