Assessment of strain bursting in deep tunnelling by using the finite-discrete element method
Assessment of strain bursting in deep tunnelling by using the finite-discrete element method
复制标题
DOI：
10.1016/j.jrmge.2018.06.007
复制
发表时间：
2019-02
影响因子：
7.3
通讯作者：
I. Vazaios;M. Diederichs;N. Vlachopoulos
中科院分区：
文献类型：
--
作者：
I. Vazaios;M. Diederichs;N. Vlachopoulos
岩爆是一种复杂的现象，在硬岩和高地应力条件下的深埋隧道开挖的设计和施工阶段都面临着重大挑战。虽然当地经验、现场监测和丰富的数据分析是管理灾害和相关风险的常用工具，但基于不连续体建模的先进数值技术也显示出协助评估岩爆的潜力。在这项研究中，混合有限元离散元法（FDEM）调查的故障和断裂过程，和能量储存和快速释放的机制，导致爆裂，以及评估其效用的一部分，地下开挖的设计过程。在数值模型的校准，以模拟深开挖在一个坚硬的，大块的岩体，离散裂隙网络（DFN）的几何形状集成到模型中，以检查岩石结构的影响，岩爆在高的原地应力。所获得的分析结果不仅突出了显式模拟模型中预先存在的接缝的重要性，因为它们影响动员的破坏机制和应变突发现象的强度，而且还显示了所采用的接缝网络几何形状，现场应力条件及其相互作用如何影响开挖引起的损伤的程度和深度。此外，一个严格的质量和速度的弹射岩石块和比较所获得的数据与成熟的半经验方法的分析表明，该方法的潜力，以提供现实的估计在爆裂过程中释放的动能，以确定能源支持的需求。
Rockbursting in deep tunnelling is a complex phenomenon posing significant challenges both at the design and construction stages of an underground excavation within hard rock masses and under high in situ stresses. While local experience, field monitoring, and informed data-rich analysis are some of the tools commonly used to manage the hazards and the associated risks, advanced numerical techniques based on discontinuum modelling have also shown potential in assisting in the assessment of rockbursting. In this study, the hybrid finite-discrete element method (FDEM) is employed to investigate the failure and fracturing processes, and the mechanisms of energy storage and rapid release resulting in bursting, as well as to assess its utility as part of the design process of underground excavations. Following the calibration of the numerical model to simulate a deep excavation in a hard, massive rock mass, discrete fracture network (DFN) geometries are integrated into the model in order to examine the impact of rock structure on rockbursting under high in situ stresses. The obtained analysis results not only highlight the importance of explicitly simulating pre-existing joints within the model, as they affect the mobilised failure mechanisms and the intensity of strain bursting phenomena, but also show how the employed joint network geometry, the field stress conditions, and their interaction influence the extent and depth of the excavation induced damage. Furthermore, a rigorous analysis of the mass and velocity of the ejected rock blocks and comparison of the obtained data with well-established semi-empirical approaches demonstrate the potential of the method to provide realistic estimates of the kinetic energy released during bursting for determining the energy support demand.