Overview The National Highways Authority of India (NHAI) has initiated a comprehensive geotechnical investigation across the entire NH-66 expansion project in Kerala. This action follows the recent collapse of a reinforced soil (RS) wall at Mylakkadu in Kollam, raising concerns about structural integrity and public safety. Key Developments Geotechnical Investigation Scope: The investigation covers all 18 highway projects along NH-66 in Kerala. Agencies Involved: 18 geotechnical agencies have been employed. Locations: A total of 378 RS wall locations will be assessed. Timeline: Tests at 100 locations within the first month, with the entire assessment completed within three months . Mylakkadu RS Wall Collapse The collapse of the RS wall at Mylakkadu, part of the approach structure to a vehicular underpass on the Kollam–Kadambattukonam section of NH-66 , has been attributed to a fundamental geotechnical problem. Cause: Preliminary assessments indicate a deep-seated shear or bearing capacity failure. Height of Wall: The collapsed wall was 9.4 meters high. Expert Committee and Safety Audits Following the Mylakkadu failure, a high-level expert committee was dispatched to the site on December 6, 2025 , to investigate the causes and recommend corrective measures. Expert Team Members: Jimmy Thomas (IIT-Kanpur) and T.K. Sudheesh (IIT-Palakkad). Expanded Safety Audit: Following an incident on the Aroor-Thuravoor elevated road project, RITES is conducting a safety audit expanded to cover all NH-66 projects. Remedial Measures and Quality Assurance The NHAI has affirmed that field and lab reports will serve as the basis for re-checking the design and construction of every RS wall. Remedial measures, including dismantling and complete reconstruction, will be mandated where necessary. Stringent Review: No RS wall will be accepted until the review process is complete and quality standards are fully confirmed. UPSC Relevance This news is relevant to GS3: Infrastructure , specifically road infrastructure development and maintenance. It also touches upon aspects of GS3: Disaster Management , considering the structural failures. The involvement of institutions like IIT-Kanpur and IIT-Palakkad highlights the role of technical expertise in infrastructure projects. Potential UPSC Questions Discuss the challenges in maintaining the quality of highway construction in India. Evaluate the role of geotechnical investigations in preventing infrastructure failures. Analyze the measures taken by NHAI to ensure the safety and stability of national highways. Important Facts The geotechnical investigation spans across 18 highway projects on NH-66 in Kerala. 378 RS wall locations are under assessment. The expert committee included members from IIT-Kanpur and IIT-Palakkad . RITES is conducting a safety audit on NH-66 projects.