Project Facts and Numbers

• Project Name: Providing and Laying RC pipe sewer line from Anik Wadala to CST Road Junction by Micro-tunneling and Pipe Jacking Methods
• Location: Anik Wadala to CST Road Kurla Junction
• Total Area Served: 675.54 hectares
• Total Length of Sewer Line: 5,063 meters
• Ground Improvement Length: 3,746.40 meters
• Ground Improvement Area: 25,475 square meters

Purpose

The primary objective of the T-3 Project is to provide an efficient sewerage facility for the Anik Wadala area, facilitating the safe disposal of wastewater from Anik Wadala to CST Road Kurla in the F/N Ward, M/West, and L Ward.

Benefits

The sewerage facility will benefit an extensive area of approximately 675 hectares, including:

• F/N Ward: Bharni Naka, Sangam Nagar, Pratiksha Nagar, Antop Hill, Anik-Wadala Area, Kokari Agar
• M/West Ward: MMRDA and Bhakti Park Area
• L Ward: Shivshrushti Nagar Area, Kurla

Challenges

The project faced several challenges due to the cohesive soil structure (Montmorillonite), low bearing capacity, and buoyancy effects. The primary challenges included:

• Cohesive soil with no particle friction and low bearing capacity (0-2 SPT)
• Pipe floatation due to buoyancy
• Subsoil water and tidal effects

Solutions Implemented

• Ground Improvement: Utilized lime stabilization in marine clay to enhance soil properties.
  • Cation Exchange: Reacted with siliceous components of clay.
  • Flocculation: Improved strength properties through rapid flocculation.
  • Crystallization: Enhanced long-term strength with calcium silicate hydrate and calcium aluminate hydrate gels.
• Engineering Adjustments:
  • Low RPM and constant forward movement to avoid settlement
  • Lightweight gear and smaller motor to reduce TBM weight
  • Center of gravity optimization to prevent dive risk
  • Specially designed cutter wheel and M50 grade RCC pipe with HDPE liner

Special Technologies Used

• Lime Stabilization: Improved marine clay ground conditions via cation exchange, flocculation, and crystallization processes.
• Nalla Crossing Methodology: Implemented concrete channels supported by bearing piles for sewer line stability under S.W. Nallas, with proper signage for alignment and coordination with the SWD Department.

The T-3 Project successfully addressed various engineering and logistical challenges, providing a crucial infrastructure upgrade to support the growing needs of the Anik Wadala area.