高地应力条件下隧道TBM施工岩爆分析

高应力条件下,地下工程在脆性岩体中施工很容易导致岩爆的发生。以N-J水电站大埋深引水隧洞为研究对象,首先采用应力解除法进行现场地应力测试,发现引水隧洞的地应力以构造应力为主,最大主应力达到了107 MPa,较高的地应力水平是导致现场岩爆发生的主要原因。为进一步分析引水隧洞岩爆规律,将地应力场转换至隧道局部坐标,在考虑地应力场剪应力影响的情况下,采用能量判据,通过数值方法计算得到了岩爆的分布范围。

Analysis of rock burst of TBM tunnel excavation under high ground stress

Under high ground stress, the rock burst is easily induced by the excavation of underground engineering in brittle rock mass. Taking the large overburden diversion tunnel excavation of N-J hydroelectric project as a case, the stress relieving method was firstly adopted in in-situ test. According to the results of ground stress test, the tectonic stress is the dominated ground stress and the maximum principal stress is up to 107 MPa, which is the main cause of the rock burst. Furthermore, to an-alyze the rock burst law of diversion tunnel, the ground stress field is transformed to the local coordinate of the tunnel; by the consideration of the shear stress effect of ground stress field, the distribution range of rock burst is calculated by using the numeri-cal method, which is compared with the field monitoring results.