Repairs at Pragati Maidan in Delhi tunnel start
The official said that in an attempt to tackle the problem of water seepage inside the tunnel, the “injection grouting” method is being deployed
The Public Works Department (PWD) has begun to fill the cracks at the Pragati Maidan tunnel with liquified cement under high pressure and rectifying the slope gradients in the drains — under the first phase of the repair work being carried out at the tunnel — a senior PWD official aware of the matter said on Wednesday.
The official said that in an attempt to tackle the problem of water seepage inside the tunnel, the “injection grouting” method is being deployed to heal the cracks that have appeared over the last year.
“We have identified cracks at nine locations. The grouting repair work at the first sample site has been completed towards the tunnel portion near gate no.7. Under this process, liquified cement-like material comprising water, cement, and other additives are injected at very high pressure inside the cracks to restore the structural integrity and prevent seepage. The method uses different types of material depending on the size and location of the crack and the emulsion is injected at high pressure to ensure that no air bubbles remain,” the official said.
The grouts used to seal the cracks usually include materials like cement, polyurethanes, epoxy resins and silica-based materials.
On Tuesday, the traffic police had announced that the tunnel will remain closed for repair work from midnight to 6am till April 18, 2024. The tunnel will also remain closed for the entire day on three Sundays over this period — March 24, March 31 and April 7.
The official quoted above added that the agency is targeting to complete the repair work in 12-15 days. “The second component of the work includes slope correction in the drain along the tunnel wall. The drain is being dug up to make it deeper and the gradient will be maintained in a manner that even if there is excess water, it should get cleared in a short period,” he said.
The Pragati Maidan complex and the integrated transit corridor were developed along with Bharat Mandapam ahead of the G20 Summit 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 the cost of ₹777 crore.
On February 3, PWD issued a show cause notice to the construction company to initiate the repair work and rectify technical and design deficiencies in the project. PWD had identified 12 issues including continuous leakage, large cracks, waterlogging, and malfunctioning of drainage systems, among others.
PWD on March 18 also formed an expert committee comprising a deputy general manager of Delhi Metro and four engineers to study the remedial measures.