Influence of weak planes on rockburst occurrence
Abstract
Geological structures such as faults, joints, and dykes have been observed near excavation boundaries in many rockburst case histories. In this paper, the role of weak planes around tunnels in rockburst occurrence was studied. An Abaqus explicit code was used to simulate dynamic rock failure in deep tunnels. Firstly, Abaqus’s usefulness for modeling geomaterials was improved by introducing material heterogeneity using Python scripting. Modeling results showed that heterogeneous models resulted in more realistic failure modes than homogeneous models. Secondly, rock failure near the excavation boundary of a tunnel without any adjacent geological structure was modeled and released kinetic energy from rock due to failure and velocity of elements at the tunnel wall were calculated. Then, a weak plane was added to the model. This resulted in more released kinetic energy and higher element velocity, indicating that rock failure became more violent in the models with weak planes. The modeling results confirm that the presence of geological structures in the vicinity of deep excavations is a condition for the occurrence of rockburst. It explains localized rockburst occurrence in civil tunnels and mining drifts. The presented methodology in this paper for rockburst analysis can be useful for rockburst anticipation and control during mining and tunneling in highly stressed grounds.References
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