A novel closed-form solution for circular tunnels in cohesive-frictional soils using isogeometric analysis, upper bound limit analysis, and soft computing Authors Toan Nguyen-Minh, Tram-Ngoc Bui, Jim Shiau, Tan Nguyen, Trung Nguyen-Thoi Publication year 2025 Index (WoS/Scopus) WoS Publisher Elsevier Journal COMPUTERS AND GEOTECHNICS Link https://doi.org/10.1016/j.compgeo.2025.107104