Stability Analysis For Surrounding Rock Of Deep Tunnel

In the light of rock mass stress redistribution due to deep underground mining andinteraction between surrounding rock and the support structure, a elastic-plastic finite elementmodel about stability analysis of surrounding rock is established in the paper. And theconcrete analysis is made about the mine engineering problem."First apply pressure, then excavate" must be obeyed when make computable analysisabout underground engineering due to it difference from surface architecture. Computablestress is the real stress, while computable displacement must subtract the start displacement isthe displacement due to excavation. Because stress scope influenced by cable anchor andbolting support is very limit, to avoid making non-liner analysis in the large model, selectvalid rock mass anchored by cable anchor joining in the finite element analysis in the form ofimproving c ,φ values to simulate the effect of cable anchor and bolting support.To talk about different support styles, three support schemes are considers in the paper inthe following:1. shotcreting around all the cross section, cable anchor and bolting support around allthe cross section.2. shotcreting only above part of the cross section, cable anchor and bolting support onlyabove part of the cross section.3. shotcreting in the proof and highwall, cable anchor and bolting support in the proofand highwall.Computable results show that, the displacement,stress and strain around undergroundbuilding obey the general elastic-plastic mechanics law after excavation.The paper makes analysis of large scale goaf after excavation and supported by cableanchor and bolting in the displacement,stress and strain,and also gives evaluation of theanchor effect. The result shows that, for the small scale stage excavation the stress anddisplacement of rock mass would be proved in the effect of cable anchor, while for the abovelevel the real effect is not obvious. About this research, because the engineering test isdifficult, the result is primary, expect scholars of this domain in a common effort to discussdeeply.