The TPT4800 earth pressure balance shield machine delivered an outstanding performance during the construction of the Shanghai Zhuyuan Bailonggang Sewage Connecting Pipe Project. It successfully completed the tunnel excavation works of the bid section. Featuring an exclusive innovative construction system and stable equipment performance, the machine effectively overcame the construction difficulties of soft soil strata and strongly supported the high-quality and efficient progress of the project.

The construction corresponds to the first section of Bid Section 1.1 (south section) of the Shanghai Zhuyuan Bailonggang Sewage Connecting Pipe Project, with a total tunnel length of 900 meters and a designed segment outer diameter of 4.6 meters. The tunnel mainly passes through clay and silty clay strata. These soft soils feature high water content and poor structural stability, which easily cause stratum disturbance, poor muck discharge and limited tunneling efficiency during construction. The complex working conditions impose extremely high requirements on equipment adaptability, muck discharge stability and tunneling control accuracy, which cannot be met by conventional construction technologies.

To address the special geological conditions and construction pain points of the project, the closed earth-pressure-to-slurry muck removal system, jointly developed by our company and Shanghai Jinshan Municipal Engineering, was successfully applied on site. Combined with the superior overall performance of the TPT4800 earth pressure balance shield machine, the innovative system perfectly adapts to the local clay and silty clay strata. It effectively eliminates the drawbacks of traditional muck discharge methods in soft soil construction, optimizes muck transportation and chamber pressure balance control, greatly improves stratum adaptability and construction stability, and solves multiple technical difficulties in soft soil tunnel excavation.

Empowered by the reliable tunneling performance of the TPT4800 shield machine and the technical advantages of the new closed earth-pressure-to-slurry muck removal system, the project achieved a substantial improvement in construction efficiency with remarkable on-site results, achieving an excellent maximum daily tunneling progress of 35 meters. Throughout the construction period, the equipment operated steadily with precise stratum control. No settlement or stratum disturbance risks occurred. The tunnel excavation proceeded efficiently and in compliance with safety standards, fulfilling all construction indicators with high quality.

The smooth completion of the Shanghai Zhuyuan Bailonggang Sewage Connecting Pipe Project fully demonstrates the superior performance of the TPT4800 earth pressure balance shield machine in urban sewage tunnel engineering. It also verifies the unique technical advantages of the closed earth-pressure-to-slurry muck removal system in soft soil tunneling. The project accumulates mature and reliable construction experience for urban municipal sewage tunnels and long-distance tunneling in soft strata, facilitating the upgrading and high-quality development of urban municipal pipe network infrastructure.