Although tunnels may look different from country to country and location to location, they have one thing in common: tunnel construction comes with its challenges. Acknowledging the complexities involved in tunnel construction, which can include geological, engineering, and logistical challenges is a given, and though there may be many elements out of one's control, introducing a Brokk robot into the mix means that you can predict the future outcome of the project, and know that it will be successful.

Diamond Drilling SRL successfully widened a tunnel in Bulgaria with a tight one-month deadline. If that wasn't a challenge in itself, this particular project was undertaken in November; known to be a cold and rainy period in Bulgaria, further complicating the tunneling project. Diamond Drilling SRL attributes the success of the project to the use of Brokk demolition robots, their unmatched versatility and unparalleled reliability. Let's dig a little deeper into the specifics of their success story.

The project in numbers

Diamond Drilling SRL is a global company specializing in concrete cutting and grading services who was recently tasked with a tunneling project in Bulgaria. They were tasked with widening an existing tunnel using a BROKK 200 and BROKK 520D to perform the bulk of the demolition project. The tunnel, which was 100 meters long (328 feet), required a 9-meter (30 feet) by 1.8-meter (5.9 feet) expansion at its midpoint. The original tunnel diameter was 3.2 meters (10 feet), and they were tasked with increasing it to 7 meters (23 feet), meaning a total of 25 meters (82 feet) of concrete and 150 cubic meters (304 sq feet) of granite needed to be safely removed. The 9-meter (30 feet) expansion included the installation of metal arches and SHOTCRETE CONSOLIDATION between each stage, for a total of seven stages.

The project objectives

• To effectively and efficiently widen the tunnel using Brokk demolition robots.
• To complete the tunneling project within a one-month timeframe.
• To ensure the structure of the tunnel remain intact during the widening process.
• To manage the challenges caused by harsh weather conditions and groundwater infiltration.

Time was of the essence

Tackling tough concrete and granite with precision and efficiency was a no-brainer for the Brokk 200 and Brokk 520D, but a tight one-month timeframe required a highly organized and efficient methodology. Furthermore, Diamond Drilling SRL also needed to divert the groundwater flow away from the jobsite in order to reduce the water level and minimize disruptions during demolition. Since the widening of the tunnel was undertaken in November, the temperature requirement for the shotcrete application – a crucial component of the consolidation process – was 5°C (41°F) or above. Managing time and harsh weather conditions while ensuring the structural integrity of the tunnel meant that the demolition equipment used to undertake this project needed to offer reliability, safety, and precision, as one wrong move could have irreversible and costly damages. In short, a lot was at stake.

''The safety, particularly in handling confined spaces, groundwater, and tight timeframes proved crucial,'' said Youssef Hallak, Managing Director of Diamond Drilling SRL. ''The versatile, precise, and powerful capabilities of Brokk robots proved invaluable in navigating the project's unique challenges.''

Renowned for their versatility and agility, Brokk demolition robots allow operators to conduct demolition work in confined spaces and navigate challenging terrain. ''This adaptability was crucial for accessing the tunnel walls and maneuvering within the narrow confines of the widening area,'' added Hallak.