The role of pre-existing jointing on damage zone evolution and faulting style of thin competent layers in mechanically stratified sequences: a case study from the Limestone Coal Formation at Spireslack Surface Coal Mine
The role of pre-existing jointing on damage zone evolution and faulting style of thin competent layers in mechanically stratified sequences: a case study from the Limestone Coal Formation at Spireslack Surface Coal Mine
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DOI：
10.5194/se-2019-202
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发表时间：
2020-01
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影响因子：
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通讯作者：
Billy J. Andrews;Z. Shipton;R. Lord;Lucy McKay
中科院分区：
文献类型：
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作者：
Billy J. Andrews;Z. Shipton;R. Lord;Lucy McKay
抽象的。断层和裂缝网络在地下流体流动中发挥着重要作用，可以起到增强、延迟或分隔地下水流的作用。在多层层序中，断层的内部结构和生长不仅受断层断距的控制，还受断层切割岩性的力学性质的影响。本文利用地质实地调查，结合断层和裂缝测绘，研究了 Spireslack 露天煤矿暴露的机械分层石灰岩煤层和周围岩性的内部结构和断层发育情况。我们发现断层岩的发育和断层带的复杂性取决于：a）断层是否自并置或切割多种岩性； b) 页岩的存在和行为，可能导致显着的地床旋转和断层核透镜体的形成； c) 断层发生时是否存在预先存在的弱点（例如接缝）。麦克唐纳石灰岩中预先存在的节理网络和麦克唐纳煤中的割理影响了这些岩性内的断层生长和流体流动。
Abstract. Fault and fracture networks play an important role in sub-surface fluid flow and can act to enhance, retard or compartmentalise groundwater flow. In multi-layered sequences, the internal structure and growth of faults is not only controlled by fault throw, but also the mechanical properties of lithologies cut by the fault. This paper uses geological fieldwork, combined with fault and fracture mapping, to investigate the internal structure and fault development of the mechanically stratified Limestone Coal Formation and surrounding lithologies exposed at Spireslack Surface Coal Mine. We find that the development of fault rock, and complexity of a fault zone is dependent on: a) whether a fault is self-juxtaposed or cuts multiple lithologies; b) the presence and behaviour of shale, which can lead to significant bed-rotation and the formation of fault-core lenses; and c) whether pre-existing weakness (e.g. joints) are present at the time of faulting. Pre-existing joint networks in the McDonald Limestone, and cleats in the McDonald Coal, influenced both fault growth and fluid flow within these lithologies.