The 2 km long Blue Line Underground Section is part of a 20 km long LRT line currently being developed as part of the Jerusalem Mass Transit Master Plan. The Underground Section of the Blue Line is characterized by narrow streets, limited right of way, steep gradients, small alignment radii turns and crossings with other LRT lines. The geological conditions feature different formations of limestone and dolomite. Karst is a known frequent phenomenon in the Jerusalem region which must be considered in the design and construction process. This publication describes the key criteria to be addressed in the design, such as the overall design approach for the large span station tunnels, geological risks especially in relation to karst, the impact on existing buildings and the insertion of the underground stations in a highly sensitive urban environment with very limited available space.
The 20 km long Blue Line LRT is being developed by the Jerusalem Transportation Master Plan Team (JTMT) as part of the Jerusalem Mass Transit Master Plan, connecting the neighbourhoods Ramot in the north to Malha and Gilo in the south of Jerusalem. The section of the Blue Line in the city centre runs along principal urban streets featuring a mix of commercial, business, residential, public and religious institutional uses with very intensive pedestrian traffic along the entire alignment. In addition, this section of the Blue Line is characterized by narrow streets, limited right of way, high gradients, small radii turns, and crossings with the planned Green Line LRT and the existing Red Line LRT. To avoid these constraints, it was determined to adopt an underground alignment for the city centre section.
The Blue Line Underground Section is approximately 2 km long and stretches between Giv’at Moshe Street in the north and Jaffa Street in the south at the crossing with the existing Red Line LRT. The project also comprises a 350 m long branch tunnel connecting the Blue Line to the Green Line. The main underground structures of the Blue Line Underground Section include double-track running tunnels, three mined underground stations (Bar Ilan, Yehezkel and Strauss) including ventilation and emergency escape shafts, a large-span bifurcation cavern at the junction with the branch tunnel and three portal structures (north, south, branch).
