Project Summary

The TP1.4 Section of the Taopu Waste Water Treatment Plant Project involves the construction of pipeline works connecting three major drainage systems as part of the initial rainwater regulation and storage project at the Taopu Sewage Treatment Plant.

• 6 TBM launch shafts

• 2 pipe jacking shafts

• 3254.2 meters of shield tunnel

• 777.9 meters of pipe jacking tunnel

• 3 shafts for operational and maintenance purposes.

This project is part of an effort to manage rainwater and prevent flooding by connecting key drainage systems in the area, improving stormwater control around the sewage treatment plant.

Construction Difficulties

Geotechnical difficulties:

• 32.45 meters soil overburden

• The entire tunnel section is located in a silty sand layer and an artesian aquifer with strong permeability.

• The soil layer is prone to liquefaction due to the shield tunnelling disturbance.

• These factors increase the risks of water and sand inflow at the portal, as well as surface settlement during the tunnel initiation phase.

Tunnelling Difficulties

• The tunnel involves 4 sections with sharp curves of R65m, R70m, R75m, and R80m.

• Tunnelling through these sharp curves presents several issues:

  • Increased segment ring height differences leading to difficulty in controlling tunnel alignment.

  • Tunnelling challenges such as difficulty in maintaining tunnel axis control, segment wear at the tail of the shield, and uneven gaps between segments causing leakage.

  • Hinge leakage and difficulty in controlling surface settlement due to the sharp curve.