Study on creep properties of rocks and long-time stability of shaft in high ground stress zone

According to actual demand of Jinchuan No.3 minefield, aset of bend creep experiments was performed to study the creep behavior oftypical four ore-rocks under step increment load by the developedgravitation-style rock creep test machine. The creep properties of theore-rocks were experimentally obtained. A new viscoelastic-plastic model ofhomogenous mixed rock, named improved Burger's creep model, was thenestablished by combining the Burger's creep model and experimental data withMohr-Coulomb criterion, whose parameters values were achieved by using amixed technique of pattern search and non-linear least -square regression.The theoretic curves of the improved Burger's creep model are in goodgreement with those of the creep tests for homogenous mixed rock, to showthat the improved Burger's creep mode can be applied to describe the creepcharacteristic of homogenous mixed rock. Furthermore, based on creepparameters values, the three -dimensional creep numerical simulation ofrepaired main shaft and its horsehead engineering was conducted by adoptingthe improved Burger's creep model. Reasonable suggestion and evaluation forthe long-term stability and safety of repaired main shaft were put forwardon the basis of the simulaton results.