MMRC floats tender for Geotechnical Work on Mumbai Metro Line 11

Mumbai, India (Metro Rail Today): Mumbai Metro Line-11, also known as the Green Line, is advancing with a new phase as the Mumbai Metro Rail Corporation Ltd. (MMRC) has recently called for bids to conduct geotechnical soil investigations. This crucial 18-kilometer extension, designed to connect Anik Bus Depot to SPM Chowk via 15 underground stations, represents a significant leap forward in enhancing Mumbai's urban transit infrastructure. Here’s a closer look at the developments surrounding this project.

Significance of the Geotechnical Investigation

The geotechnical investigation is a pivotal step in the construction of Mumbai Metro Line-11. It aims to gather detailed data on the sub-soil conditions along the proposed route. This data is essential for designing and constructing the metro's underground structures safely and efficiently. The investigation will help in selecting suitable construction methods, machinery, and technologies, minimizing potential damage to existing structures during the construction phase.

Scope and Specifications of the Investigation

The geotechnical investigation will involve drilling boreholes at regular intervals along the alignment of the twin tunnels. The key specifications include:

• Borehole Specifications: Drilling of 150mm diameter boreholes at 500-meter intervals.
• Station-Specific Drilling: Three boreholes at each station site.
• Drilling Depths: Boreholes will be dug to depths of 10 meters, between 10-20 meters, and beyond 20 meters as outlined in the consultant's plan.

This comprehensive approach will provide crucial insights into the sub-surface conditions, which are vital for the project’s success.

Timeline and Key Dates

The geotechnical investigation is set to be completed within 90 days. Key dates to note include:

• Submission Due Date: August 21, 2024, at 4.00 PM
• Technical Bid Opening: August 22, 2024, at 4.00 PM

These deadlines emphasize MMRC’s commitment to advancing the project efficiently and ensuring all necessary preparations are made before construction begins.

Project Alignment and Station Details

Mumbai Metro Line-11’s alignment has been revised, with the latest tender notices detailing the 15 underground stations along the route:

• Anik Bus Depot
• Wadala Depot
• CGS Colony
• Ganesh Nagar
• BPT Hospital
• Sewri
• Hay Bunder
• Coal Bunder (Darukhana)
• Reay Road
• Byculla
• Nagpada Junction
• Bhendi Bazaar
• Crawford Market
• CSMT Metro (Interchange with Line-3 / Aqua Line)
• Horniman Circle
• SPM Circle

This alignment ensures that Line-11 will offer critical connectivity across major areas in Mumbai, integrating seamlessly with the city’s existing metro network.

Requirements for the Geotechnical Report

Upon completion of the investigation, the geotechnical contractor will be required to submit a detailed report including:

• Borehole Details and Locations: Geo-referenced coordinates.
• Area Geology and Characteristics: Understanding the geological makeup of the area.
• Water Table Levels: Essential for determining foundation depths and construction methods.
• Test Results: Comprehensive data from soil tests.
• Borehole-Wise Foundation Recommendations: Custom recommendations for each location.
• Cutoff Value and Soil Bearing Capacities: Important for structural stability.
• Seismicity Analysis: Ensuring earthquake resistance.

These elements are critical to ensuring that the construction of Mumbai Metro Line-11 is carried out safely and effectively.

Future Steps and Project Timeline

The geotechnical investigation is just one phase in the broader scope of the Mumbai Metro Line-11 project. Future steps include:

• Securing Financing: Ensuring financial viability for the project.
• Preparing Detailed Designs: Finalizing architectural and engineering plans.
• Appointing a General Consultant: Overseeing the project’s progress.
• Conducting Environmental and Social Impact Assessments: Ensuring compliance with regulations.
• Rehabilitation Planning: Addressing impacts on affected communities.

Given the scale and complexity of the project, construction is not expected to commence until at least 2027, and this timeline remains optimistic. Nonetheless, the meticulous planning and preparation by MMRC aim to ensure a smooth transition into the construction phase when it begins.

The invitation for bids for the geotechnical investigation on Mumbai Metro Line-11 marks a crucial milestone in the project’s development. As MMRC progresses with these foundational steps, Mumbai is poised to benefit from improved connectivity and a more efficient public transport system. Each step taken brings the city closer to realizing a robust and modern metro network, promising significant enhancements to urban mobility and infrastructure.