EPB Shield: Safe in soft ground.
Herrenknecht Earth Pressure Balance (EPB) Shields are in their element in soft ground. EPB excavation is ideal for cohesive or incohesive soil with a high clay or silt content and low water permeability.
data sheet download
Water tunnel Bangkok, Thailand
The excavation of a 3,300m water tunnel with segment lining is to not disturb traffic or damage the environment as well as not risk ground settlement. When tunnelling underneath the road at a 90-degree gradient, 20 concrete pillars need to be avoided. The tunnel segments are especially designed for the project, which means that the TBM needs to be adapted to the tunnel diameter. The customer decides to use a Herrenknecht EPB3776AH (boring diameter 4,310mm). The required maximum deviation of +/- 40mm called for top precision. The minimum tunnel face pressure of 1.5 bars and the closely coordinated ground conditioning of the foam generator ensured fast advance. Ten tight curves need to be mastered at a depth of 18m. A track system inside the tunnel for transporting lining segments and concrete is made for just-in-time tunnelling. The excavated material can be removed on the way back.
download tunnelling project data sheet.
Sewage tunnel in Szeged, Hungary
A 3.45km collector is to connect the new water treatment plant near the winter port south west of Szeged to the existing sewage system near the freight station. A Herrenknecht EPB2000 drives underneath a nature reserve and residential areas, as well as roads with restricted space. The tunnel route consists of 6 straight stretches, some of which are more than 500m in length and a curved stretch with a radius of 800m. Excavation work starts in April 2005 from the site next to the levee of the winter port, and below the water level of the Tisza river. Shortly after work starts, a flood warning is issued by the city. The EPB2000 copes with the high ground water level without any settlements or other problems. The site team achieves maximum daily advances of 37m.
download tunnelling project data sheet.
Sungei Pandan River Crossing, Singapore
The Singapore project requires excavating two cable tunnels underneath a marine bay with difficult geological conditions. To make matters even more complicated, a horizontal and a vertical curve have to be excavated (three-dimensional curve). The customer decides to use a Herrenknecht-EPB2000. Ground conditioning allowes safe excavation of limestone, clay, fine sand and silt. To prevent heavy wear of the disks as a result of the heterogeneity of the soil, additional wear-protection plates are welded onto the cutterhead.
