Influencing Factors of Time-space Characteristics of Delayed Rockburst in Tunnel Under High In-situ Stress
Delayed rockbursts occurred frequently in Mufeiling Tunnel in Zhejiang Province,but there was insufficient research on the influencing factors of time-space failure characteristics.Based on the field rockburst statistics and in-situ stress test,this paper explained the spatial and temporal distribution characteristics and main causes of delayed rockburst.The law of delayed rockburst under different influencing factors was analyzed by finite difference software.The results show that,the delayed rockburst accounts for about 13%of all statistical rockbursts in the field,mainly in moderate intensity,and it has obvious spatial and temporal damage characteristics.Under the action of high horizontal stress,the local strain energy density around the cave is large,meanwhiles,with the conditions of local joint fissures more developed,it is easy to induce rockburst.With the gradual increase of horizontal tectonic stress,the possibility of delayed rockburst increases significantly,and shows a trend of transition to sudden rockburst.The smaller or larger stress release coefficient will lead to the occurrence of rockburst.Therefore,it is suggested that the initial support can effectively inhibit the occurrence of delayed rockburst when the stress release coefficient of surrounding rock is 30%～60%.The above results provide a basis for predicting and inhibiting the occurrence of delayed rockburst.
hard rock tunneldelayed rockburstin-situ stress testnumerical simulationelastic strain energy
万方数据
维普
