Shanghai Taopu Waste Water Treatment Plant Tunnel Project

A construction site of a underground tunnel with yellow safety barriers, electrical cables, and signs in Chinese. The tunnel is circular in shape with a partially built structure.

Φ 4.91m KOMATSU Slurry-Shield TBM

Project Year: 2024

A map showing the layout of a pipeline with various pipe segments, indicated by different colors and labels. The map includes annotations of pipe radii and lengths, with starting points, junctions, and directional flow, along with legend icons explaining pipe types.

Project Overview

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.

Jello-Mud Result

Stable pressure is established at the tunnel entrance.

  • During the sequential opening and closing of the reserved holes in the portal, Jello-Mud is fully extruded without any gas or liquid leakage.

  • When the ball valve at the observation port of the backfill grouting hole is opened, Jello-Mud is extruded without any gas or liquid leakage.

  • Jello-Mud exhibited void-filling, sealing, and water proofing capabilities

  • Contractor was able to save 85% of portal-sealing material budget compared to using cement grout to seal the entrance ring

No leakage at the tail-seal

  • With increased grouting rate during turning, no leakage was observed at the tail-seal.

Diagram of a water leakage repair process showing reinforced area, sealing box with Jello-Mud, and no water leakage. The bottom row displays four numbered sections: +3, +2, +1, and -1, indicating different levels or stages.

Illustration of Jello-Mud sealing the TBM entrance ring

A construction worker in red pants is holding a broom and sweeping debris on a concrete floor in a building under renovation. There are exposed wires, electrical outlets, and construction tools around.
Three kitchen images showing a brown, molds clay-like mixture; the mixture in a bowl; and the mixture spread underneath a metal grate, ready for baking.

Site image of entrance ring with extruded Jello-Mud. No water or soil leakage was observed. Photo (right) is the extruded Jello-Mud vs fresh Jello-Mud in the v1 Pump. Similar condition of two Jello-Muds exhibits Jello-Mud’s anti-dilution ability.