Materiały konferencyjne SEP 1993 - tom 2

Underground Exploitation School '93 CONE BOLT YIELDING TENDON FOR SUPPORT OF TUNNELS: The problem is very sinriildr to that encountered in stopes • to design a system that can yield and that spreads the restralning forces as evenly across the wali rock as possible, and in the case of rockbursts to absorb the kinetic energy imparted to the rock by seismic ground motion. The problems In stopes and tunnels are the same, the solution are totalły different. A basie element reguired for the tunnel support system is a yieiding tendon. The reąulrements for the design of yielding tendons (1987 guideiines) : 1. Amount of work ta be done : > 25kJ 2. Static yield load : lOOkN 3. Mean dynamie yield load : > 5 0 kN for tendons which can yieid by 500mm. A modest minimum figurę of 25kJ per tendon is sufficient to arrest a 2m chick slab in the sidewall accelerated to a ve)octity of 3m/s or 0.95m slab in the hangingwall, assuming a tendon spacing of In the light of current knowledge, a figurę of 50kJ/m' would appear to be a better specification. Z p o i 1 6 0 - 1 2 0 - ^ 8 0 - / I Th* crIt«rIon of f Wł 2 S k J l s n et MtłsflAd t 50 kJ A m - - I r S^: MinimumryWd : @ 1 — I — I — I — I — I — I — I — r 1 0 0 2 0 0 3 0 0 4 0 0 Displac^ment (mm) 2 5 k J 5 0 0 P*rform«nc* of eorTV#ntloftai rock t#ndonft OH^Inal d0Bign •p#ctflc«tlons Actual ptrformanct of eon# bołt 122 Tom II