Evidence-Graded Global Database of Tunnel Collapses, Fires, and Severe Underground Losses

Tunnel failures and severe underground losses are documented in many official investigations and case histories, but cross-case learning is limited by inconsistent terminology, uneven source quality, and incomplete reporting of mechanisms and consequences. This Data Descriptor presents an evidence-graded database of reported tunnel failures and severe-loss events. Corpus Release 3.1 contains 78 incidents from 33 countries or cross-border settings: 19 Grade A records supported by official investigations, 23 Grade B records supported by peer-reviewed or technical sources, and 36 Grade C contextual records; the primary A/B subset contains 42 incidents, each linked to the source on which its grade rests. Every incident is linked to a source register, field-level uncertainty table, six-step causal chain, chronology, and audit log; 35 records of the previous release were removed after source verification, and every coded consequence value was checked against a source. The schema separates immediate mechanisms from geotechnical triggers, structural or system failures, operational and management contributors, warning status, and consequences; these explanatory fields are coded for the Grade A records. Results are reported by evidence stratum rather than as a global census. The Mendeley Data package supports reuse, audit, correction, and versioned expansion.