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论文类型：期刊论文

发表时间：2012-09-01

发表刊物：ROCK MECHANICS AND ROCK ENGINEERING

收录刊物：SCIE、EI、Scopus

卷号：45

期号：5,SI

页面范围：753-765

ISSN号：0723-2632

关键字：Numerical simulation; Hydro-mechanical behaviour; Fracture propagation; Damage; Heterogeneity; Rock

摘要：In order to better understand opening-mode fracture initiation and propagation perpendicular to the bedding plane at depth in sedimentary rocks, a series of two-dimensional (2D) numerical simulations is conducted. First, the stress states between two adjacent fractures for a typical three-layer model with pre-assigned fractures are simulated. Second, the same three-layer model without pre-assigned fractures is adopted to study the initiation and propagation of fractures in layered rocks. Numerical results show that infilling fractures grow more easily from flaws located near the interface than from those in the middle of the fractured layer. Flaws can begin to propagate to form a complete infilling fracture when the size of the flaws exceeds half of the thickness of the central layer. Under different overburden stress conditions and internal fluid pressure, the numerically obtained ratio of the critical fracture spacing to layer thickness varies between 0.465 and 0.833. This range encompasses the often-cited ratios of spacing to layer thickness in the literature for well-developed fracture sets. In addition, both the fracture pattern and the critical value of the fracture spacing to layer thickness ratio are strongly dependent on the heterogeneous characteristics of the central layer. In cases with a relatively homogeneous central layer, more interface fractures occur, and the interface delamination evidently influences the fracture saturation.