Delhi: PWD completes repairs at Pragati Maidan tunnel

:The Public Works Department (PWD) has completed the repair work at the Pragati Maidan tunnel within a month, after the agency found cracks on the surface of the tunnel from inside, officials aware of the development said. The repair work had been taken up on March 20.
The committee, that had been formed to look into the structural condition of the tunnel is yet to submit its report, they added.
PWD officials said that the repair work included two main tasks of filling the cracks with liquified cement under high pressure and rectifying the slope gradients in the drains. Currently, routine maintenance work is going on, they added.
“We had expected to complete the work in about 20-25 days, which is now done and the improvements have been made. Routine maintenance like cleaning of drains is going on now. For the repair work, the tunnel was already shut at night for almost a month. Since the tunnel cannot be closed at night now, we have put up barricades and are trying to complete the routine maintenance during weekends, when the traffic pressure is low,” said a senior PWD official.
To handle water seepage inside the tunnel, officials used the “injection grouting” method to repair the cracks. As part of this method, liquid concrete is injected into the cracks to fill them up, which is then allowed to dry.
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PWD had earlier stated that cracks were found at nine locations where injection grouting was done. The grouts used to seal the cracks usually include materials like cement, polyurethanes, epoxy resins and silica-based materials. Apart from filling the cracks, PWD also dug up the drains to make them deeper ahead of the monsoons and to ensure slope correction so that the rainwater is drained out quickly.
The department had earlier claimed that the tunnel was designed with seven high-capacity sumps fixed with automatic pumps along it for drainage that can handle heavy rainfall over the next 100 years. The design was prepared based on rainfall data from the past 15 decades. Officials aware of the matter said, that all seven sumps of different sizes have the capacity to drain around 950 litres per second of water, the largest one having a capacity of 409 litres per second. However, following heavy rainfall during monsoon last year, the tunnel was flooded and had to be shut for four days to drain out the water.
The Pragati Maidan complex and the integrated transit corridor were developed along with the Bharat Mandapam ahead of the G20 Summit in Delhi and the main 1.3-km-long tunnel and five underpasses in its vicinity were launched by Prime Minister Narendra Modi in June 2022. The project was inaugurated in 2022 at a cost of ₹777 crore.
On February 3, PWD issued a show cause notice to the construction company of the tunnel to initiate the repair work and rectify technical and design deficiencies in the project after it found cracks. The department had identified 12 issues, including continuous leakage, large cracks, waterlogging, and malfunctioning of drainage systems, among others. On March 18, an expert committee was formed by PWD comprising a deputy general manager of the Delhi Metro and four engineers to study the remedial measures. The report of this committee is still awaited.