高地应力隧道滞后型岩爆时空特征影响因素

Influencing Factors of Time-space Characteristics of Delayed Rockburst in Tunnel Under High In-situ Stress

木匪岭隧道滞后型岩爆频发,对于其时空破坏特征影响因素研究不足。本文基于现场岩爆统计资料和地应力测试,阐释了滞后型岩爆时空分布特征和主要诱因。通过有限差分软件计算并总结了不同影响因素下滞后型岩爆作用规律。结果表明:滞后型岩爆约占所有统计岩爆的13%,以中等烈度为主,且具有明显的时空破坏特征。水平向高地应力作用下洞周局部应变能密度较大,加之围岩局部节理裂隙较发育,容易诱发岩爆。随着水平向构造应力逐渐提高,滞后型岩爆发生的可能性显著增加,且呈现向突变型岩爆转变的趋势。应力释放系数较小或较大都会导致岩爆的发生,建议围岩应力释放系数在30%~60%时进行初期支护,以有效抑制滞后型岩爆的发生。研究结果可为预测和抑制滞后型岩爆发生提供依据。

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.