ZVEZDA TUNNEL LINING Russian patent published in 1994 - IPC

FIELD: construction. SUBSTANCE: ZVEZDA tunnel lining has outer and inner layers. Outer layer is formed by conical surfaces 1,2,3,4 with vertexes directed to opposite sides with conjugation of adjacent cones with their concave curves and formation of right angle between their heights. Annular hollow 6 is made in the middle of outer layer. Located in annular layer 6 is inner layer 7 with under layer 8 rigidly secured to outer layer. EFFECT: higher efficiency in construction of tunnels in hard rock and soft grounds. 2 dwg