Stochastic Block Theory for the Observational Construction of Large Rock Slope

Abstract

For the excavation and the supporting of large rock slope, the observational construction method is becoming increasingly important in order to carry out the support decision immediately, by taking discontinuity distribution into account, because of the difficulty of supporting after some benches have already cut.
It is well known that slope stability is strongly controlled by discontinuity distribution in the case of the hard rock masses. Goodman and Shi (1982) proposed “Block Theory” for the estimation of slope stability considering discontinuity distribution. Key block, however, can be found out after all the discontinuity traces of the block appeare on the slope surface. In that moment, the key block is unstable and can move out of the slope.
Considering the above, the authors developed “Stochastic Block Theory” for the prediction of the key block before all the discontinuity traces of the block have not appeared on the slope, in other word, in the moment some of the discontinuity traces of the key block have appeared.
Using Stochastic Block Theory, the probability of becoming a key block can be estimated concerning the block surrounding some discontinuity traces and bench.