Spira Y, Lackner R, Pichler C, Mang H. Viscoplastic material models for soil: new insight into the soil-support interaction in NATM tunnel excavations. Arch. Mech. [Internet]. 2005 May 1 [cited 2025 Dec. 13];57(2-3):209-40. Available from: https://am.ippt.pan.pl/index.php/am/article/view/v57p209