A case study on control technology of surrounding rocks of TBM assembly chamber in underground coal mines

As a kind of newly emerged excavation equipment, the TBMs play an increasing important role in underground coal mines due to their high penetration rates, while the failure and large deformation of large cross-section TBM assembly chambers need to be controlled under combined action of high ground stresses and live loads generated by heavy TBM parts. In this research, the mechanical parameters of rock specimens and rock quality designation (RQD) were used to estimate mechanical parameters of rock masses. The numerical tests were conducted and the micro-parameters of surrounding rocks in UDEC were calibrated. A numerical model of the TBM assembly chamber was established and the disturbance characters under the original support scheme after excavation were studied. Moreover, the influences of live loads generated during the hoisting and assembling operations of TBM parts were taken into account. An optimized support scheme was proposed and examined by numerical simulation. The in situ monitoring works were conducted to verify the simulation results. The monitoring results are in good agreements with the simulation results and the optimized support scheme satisfied the demands of stability controlling of the TBM assembly chamber.