Dhaka Metro Rail

The Dhaka Metro Rail or simply the Dhaka Metro, is a mass rapid transit system serving Dhaka, the capital and largest city of Bangladesh. It is operated by the Dhaka Mass Transit Company Limited (DMTCL). Together with the under construction Dhaka BRT, proposed Dhaka Subway and Dhaka suburban circular rail, it is expected to reduce traffic congestion in the city. The metro rail network has five pla

Construction work was divided into eight packages, covering aspects like depots, stations and rolling stock.

The project was originally reported to be a 27 km (17 mi) underground metro rail line. It was later confirmed to be an elevated and underground metro rail project. In 2014, it was reported that 56 trains would run on the metro system. It was confirmed that 24 vehicles would run on the MRT Line-6. Line 6 consists of 16 operational elevated stations of 180m length each, and 20.1 km (12.5 mi) of electricity-powered light rail tracks. All of line 6, save for the depot and some of its accompanying LRT, will be elevated above current roads.

There are some specific engineering problems encountered during the construction of the Dhaka Metro and the solutions that were implemented:

1. Soil Stability Issues :

   - Problem: The varying soil conditions posed risks for tunneling, including issues with soil collapse.

   - Solution: Engineers used ground improvement techniques, such as soil stabilization and grouting, to enhance soil strength. They also employed a mixed-shield tunneling method to manage pressure and reduce the risk of collapse.

2. Noise and Vibration Control:

   - Problem: Construction activities generated significant noise and vibrations, impacting nearby residents and structures.

   - Solution: The use of noise barriers and vibration dampening technologies helped mitigate disturbances. Construction schedules were adjusted to minimize nighttime work in sensitive areas.

3. Interference with Existing Infrastructure:

   -Problem: The metro route intersected with existing roads, buildings, and utilities, leading to potential disruptions.

   - Solution: Detailed utility surveys and planning allowed for real-time adjustments. Engineers designed the metro's alignment to avoid major utilities and incorporated protective measures for existing structures.

4. Limited Construction Space:

   - Problem: The high population density meant limited space for construction activities.

   - Solution: Use of vertical construction techniques, including elevated tracks, minimized the footprint on the ground. Prefabrication of segments also allowed for quicker assembly and reduced on-site congestion.

5. Water Table Concerns:

   - Problem: The high water table in Dhaka posed challenges for tunneling and construction.

   - Solution: Engineers implemented dewatering systems to lower the water table during construction, alongside proper drainage designs to manage water ingress into tunnels.

6. Safety Concerns:

   - Problem: Ensuring safety during construction in a crowded urban environment was critical.

   - Solution: Strict safety protocols were established, including regular safety training for workers, use of personal protective equipment (PPE), and implementation of monitoring systems to ensure compliance.

These specific challenges and their corresponding solutions highlight the engineering ingenuity and planning required to realize the Dhaka Metro project.

Article Courtesy: Tahamid Shariyar Apon (CE'20)

Design Courtesy: Shantonu Das (CE'20)