Shanghai Longshui South Rd River-Crossing Project

A large construction site in an underground space with concrete walls and scaffolding. A red banner with Chinese characters is displayed at the top, and a prominent red cylindrical sign below with Chinese characters indicating a new project launch.

Φ 11.66m KOMATSU EPB TBM

Project Year: 2022

Map showing a tunnel under a river with labeled points: Entrance Shaft, South Line Tunnel, TBM Exit Point, and Huangpu River.

Project Overview

Project Summary

Route Overview:

  • South Line: 2.33 km, ending at the intersection of Gaoqing West Road and Yaolong Road in Pudong District.

  • Pudong South Line Tunnel:

    • Length: 481 meters.

    • Complexity: Despite being short, the tunnel involves high technical complexity, with shield tunnelling to be completed using the GPST method for the first time in Shanghai.

  • GPST Method (Super-Shallow Cover Shield Tunnelling):

    • Shallow Overburden: The shallowest cover in the Pudong South and North Line tunnel sections is just 1.7 meters.

    • Tunnelling Process: A 11.66-meter diameter shield machine starts at a working shaft 38 meters deep, crossing Qiantan Avenue under super-shallow cover with a maximum slope of 4.99% and a minimum turning radius of R400m in water-rich silty clay.

    • Shield Tunnel Control: High-precision control of the shield machine's tunneling posture, combined with stability measures and excavation techniques, ensures tunnel stability and minimal environmental impact.

Construction Challenges:

  • Ground Disturbance: Super-shallow tunnelling can cause significant ground disturbance and rapid surface settlement.

  • Traditional Bentonite Slurry: While it has good pumpability, its poor load-bearing and anti-washout capability isn't sufficient to stabilize the soil in such conditions.

Jello-Mud Results:

  • Injection

    • Jello-Mud is injected through reserved holes in the mid-shield to control surface settlement and stabilize the soil during the super-shallow tunnelling process.

  • Ground Settlement Controlled within Scope

    • Jello-Mud maintained ground settlement within millimetre

  • Thrust Force Reduced

    • TBM thrust force reduced by half

Graph showing geological depth changes over time with two GPS devices at the bottom, indicating measurements over time.

Settlement data of the TBM (mm)

Line graph showing data points YS1 to YS7 with values ranging from 0.93 to -5.27, indicating fluctuations over a period or categories.

Storm drain pipeline settlement data (mm)

Line graph showing the trend of data points decreasing over time, with annotations for 1D, 0.6D, 0.5D, and 0.4D along the vertical axis, on a grid background.

TBM Thrust Force data shows a steady decrease

A worker in safety gear, including an orange helmet and a high-visibility vest, is operating or inspecting a yellow laboratory machine with a touchscreen in an industrial setting.

Balsam Laboratory technician inspecting the Jello-Mud Pump v1.