Juice boring tunnel machines (TBMS) will be deployed for the construction of Twin Tunnel Road between Junction Hebbal Eseem Mall and Silk Board Junction in Bengalur.
A special special-purpose vehicle, B-Sile, has ruled out the alternative possibility of using hard rock TBMS, which are generally more suitable for heavy boulders. Although it was considered, B-Sile eventually favored TB porridge due to the geological composition of Bengalur, a combination of boulders and soil.
BS Prahlad, Director (Technical), B-Sile, said Hindu that Hard Rock TBMS was used in the tunnel project in Mumbai, but there were problems. “Instead, we decided to porridge TBM,” he said.
TBMS porridge uses hydraulic methods to transport the dug material and are best suited for mixed terrain. Namma Metro traditionally used a combination of TBMS sludge TBMS and balance against the pressure of the Earth (EPB).
“Since our terrain is mixed in nature, there is a high risk of damage to the blades of tbm of hard rocks. On the other hand, the TBM porridge uses bentonite, which allows springs or blades to adapt to the pressure exerted on the excavator, ideal for Bengalur terrain,” Mr. Prahlad explained.
Bentonite, the type of clay, plays a key role in TBM Kash operations by helping to regulate pressure.
The government has completed the use of eight TBM for the project. They will be deployed from five to six different launchers to start digging. Mr. Prague mentioned that the whole offer of the project was issued as part of the model of assembly, own, operation and transfer (boot), which means that the winning candidates will be responsible for obtaining the TBMS themselves.
When Mr Prahlad asked about the technical specifications of TBMS, he explained that it was up to the suppliers to decide whether to buy the machine directly or assemble them on a local level.
Historically, TBMS used in Bengalur (from Metro Namma) on average progress of 1.6 to 1.7 km per year. Although this tunnel project is expected to be similar effectiveness, the decisive factor will be the nature of the terrain that it encounters during the excavation.
According to Mr. Prahlad B-Sile, he only provided a report on the Borewell survey together with the offer documents in accordance with the instructions of the Ministry of Road Transport and Motorway. Any other geological analysis is the responsibility of suppliers due to the structure of the model launch model.
“The offer clearly states that support documents, such as geotechnical data, must only be considered references. The contractors are obliged to perform their own in -depth analyzes,” Prahlad said.
The detailed report of the project originally stipulated that disturbing surveys would be well carried out before the offer process. With the current model, however, the responsibility for detailed analysis is now on a successful candidate.
B-Silemi introduced offers for a 16.7 km long Twin Tunnel project to connect the city by connecting the northern and southern parts.
TJ Renukaprasad, a retired geology professor, explained that the reason for choosing a TBM sludge could be sealing the breakthrough points in the field. “Bengaluru has a hard rock terrain, which is predominantly a peninsula gneissic rock and is also affected by many rocks such as granite and dolerite. Due to geotechnical activities in the field are developed fractures;
He explained that these rocks in the field of Bengalur are over 3,200 million years old and some are 2,500 years old.
Published – August 2025 9:31 IS IS
