"Weak Soil and Lapses in Execution Led to NH-66 Wall Collapse": NHAI Acts Against Contractor

Kollam: The National Highways Authority of India (NHAI) has said that the Reinforced Soil (RS) wall that collapsed at Mylakkadu on NH-66 failed due to the poor bearing capacity and quality of the soil used in its foundation. The structure, a 9.4-metre-high approach wall for a vehicular underpass on the Kollam–Kadambattukonam stretch, came down on December 5 while construction was still underway.

According to NHAI, preliminary findings point to a deep-seated shear or bearing failure, meaning the soil at the base was not strong enough to support the fill. The agency has initiated action against the concessionaire, Shivalaya, and the Independent Engineer, Feedback–Satra JV. Both have been temporarily barred from bidding for new projects and issued show cause notices for possible debarment—up to three years for the concessionaire and up to two years for the engineering firm. Their key personnel, including the project manager and resident engineer, have been removed from the site.

NHAI said RS wall technology is well-established, but the recent failure raises concerns about the soil quality used in several NH-66 structures. A high-level expert team from IIT Kanpur and IIT Palakkad inspected the site on December 6 and will submit recommendations. The agency has also begun implementing suggestions from an earlier expert panel formed after the Kooriyad NH collapse.

To prevent similar incidents, NHAI has appointed 18 geotechnical agencies to carry out soil investigations at 378 structures and RS wall locations across 18 NH-66 projects in Kerala. Testing will begin within a week, with 100 sites to be completed in one month and the remaining in about three months. The design and construction of every RS wall will be reviewed again after these tests, and structures will be accepted only after quality is confirmed. Where required, walls will be dismantled and rebuilt. The agency said accountability will be fixed for all lapses identified during the review.

Following a separate incident in which girders fell at the Aroor–Thuravoor Elevated Road project in November, NHAI has already engaged RITES for a safety audit. This audit will now be expanded to cover other NH-66 projects to detect and address risks in advance.