Rockburst is one of the severe geotechnical problems that may occur while tunnelling under high in-situ stresses. Despite numerous studies in the relevant literature, the evaluation and prediction of the rockburst still remain a common challenge worldwide. In this paper, a self-developed combined finite-discrete element method (FDEM) is used to numerically investigate the rockbursts in deep tunnelling under high in-situ stresses. The rockbursts in the drainage tunnel at the Jinping II Hydropower Station are modelled and the effects of the geological and geotechnical characteristics of the site on the occurrence of rockbursts are investigated. The FDEM numerical modelling vividly simulates the fracture initiation and propagation, as well as the fragment expulsion, ejection and flyout resulting in the rockburst process that could be difficult to capture on the site or via the conventional continuum modellings. The effect of the pre-existing fault on the site is studied, and the critical roles of the location and the dip angle of the fault in determining the rockburst development around the tunnel are highlighted. Then, the effects of in-situ stresses on rockburst development are investigated by applying different lateral pressure coefficients in the model. It is found that based on the Jinping site condition, a low lateral pressure coefficient could contribute to the alleviation of the rockburst around the tunnel but the alleviation effect is relatively limited, while a high lateral pressure coefficient could result in the rockburst that breaks more rock masses on the tunnel surface. Moreover, the influences of tunnel shapes on the rockburst incidents are also studied by further modelling rockbursts around tunnels in square shape and horseshoe shape. It is found that the square shape is inadequate in controlling rockbursts at the roof and floor areas, and the most suitable tunnel shape to resist rockbursts in such field condition is the circular shape. By vividly reproducing the rockburst processes in deep tunnelling under high in-situ stresses and elaborating the effects of several critical geological and geotechnical characteristics on the rockburst development around the tunnel, this study contributes to the understanding of the associated rockburst mechanisms and is also of guiding importance for certain tunnelling designs and constructions in practice. It is also expected that the proposed method can be used to evaluate and predict the rockbursts in many other scenarios in future studies.

岩爆是在高地应力下掘进时可能发生的严重岩土工程问题之一。尽管在相关文献中进行了大量研究，但是岩爆的评估和预测仍然是全球范围内的普遍挑战。本文采用自主开发的组合有限离散元法（FDEM）对高地应力下深埋隧道岩爆进行数值研究。对锦屏二级水电站排水隧道中的岩爆进行建模，研究了场地地质和岩土特征对岩爆发生的影响。FDEM数值模拟生动地模拟了裂缝的起裂和扩展，以及碎片的排出，弹射和弹射导致的岩爆过程可能难以在现场或通过传统的连续介质模型捕获。研究了预先存在的断层对现场的影响，强调了断层位置和倾角在确定隧道周围岩爆发展中的关键作用。然后，通过在模型中应用不同的侧压力系数来研究地应力对岩爆发展的影响。研究发现，基于锦屏现场情况，较低的侧压系数有助于缓解隧道周围的岩爆，但缓解效果相对有限，而较高的侧压系数可能导致岩爆破碎更多的岩石。隧道表面的质量。而且，通过进一步模拟方形和马蹄形隧道周围的岩爆，还研究了隧道形状对岩爆事件的影响。研究发现，方形在顶、底板区域的岩爆控制能力不足，在这种现场条件下，最适合抵抗岩爆的隧道形状是圆形。本研究通过生动再现高地应力下深部隧道掘进过程中的岩爆过程，阐述几个关键地质和岩土特征对隧道周围岩爆发展的影响，有助于理解相关的岩爆机制，也具有指导意义。在实践中对某些隧道设计和施工的重要性。