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Spatial distribution of principal stresses in a layered elastic medium is considered in the paper. Transformations of the principal stresses across an interface between the layers are analyzed. A method for reconstructing the spatial stress distributions in layered medium from several spot measurements is proposed. The introduced approach is capable of obtaining the stable solution of the stress reconstruction problem with respect to the noise in input data. A typical layered medium is considered for which the stresses are reconstructed from few independent spot measurements of the stress state. The proposed approach may be used for solving an inverse problem of tectonic stresses reconstruction from the borehole logging data. 相似文献
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Izvestiya, Physics of the Solid Earth - In this work, we perform reconstruction of elastic stress fields by employing discrete data on the principal directions of the stress tensor in Central Asia.... 相似文献
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Yu.?A.?MorozovEmail author A.?N.?Galybin Sh.?A.?Mukhamediev A.?I.?Smul’skaya 《Geotectonics》2017,51(3):230-258
A study of the meticulously documented Paleoproterozoic swarms of basic dikes and sill-like bodies, as well as granite veins crosscutting Archean granite-gneiss country rocks of the Central Kola Geoblock of the Fennoscandian Shield, elucidates the question of geomechanical control of the spatial location of syntectonic sheetlike magmatic bodies intruding into heterogeneous structured geomedium. Based on structural analysis and mapping results, the succession of emplacement of several dike generations has been reconstructed and linked to structural parageneses of the corresponding deformation stages. We evaluate the effect of geomechanical and tectonic factors as well as the structural elements of enclosing strata on the places of dike localization, the character of their spatial distribution, morphology of particular bodies, and patterns of swarm systems. Geomechanical problems on the intrusion of single bodies and their communities are solved taking into account their interaction and the heterogeneity of the medium. The conditions necessary for transition of nearly vertical dikes into sills are discussed. 相似文献
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In the framework of plane elastic problem we use a numerical approach to study the forms of opening and paths of growth of three parallel magma fractures as a model of dyke swarm formation and development. As expected, the internal dynamic mechanism of dyke interaction distorts their shapes in comparison with a single dyke shape, and curves their paths combining them into a divergent or a convergent system. The external dynamic mechanism of regional stress tends to align the growing dyke paths in parallel to the axis of the maximum compressive stress. The external and internal mechanisms compete with each other. The impact of the internal mechanism is stronger when the ratio of the distance between dykes to their length is less, the initial parallel dyke shift in relation to each other is larger, and the differential regional stress is less. Under the opposite conditions, the external mechanism prevails. 相似文献
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A.N. Galybin A.V. Dyskin B.G. Tarasov R.J. Jewell 《Geotechnical and Geological Engineering》1999,17(3-4):267-289
The construction of stable structures in rock masses requires knowledge of the in situ stresses at the scale of excavations. However, the measurements obtained by the conventional overcoring technique are related to a small scale (centimetres). To extrapolate them to the scales of interest to rock mechanics (from meters to kilometres) requires a large number of individual stress measurements, followed by statistical analysis to avoid a considerable scatter of the measured values. In this paper, a method is proposed based on (a) large-scale surface stress and modulus measurements using the cylindrical jack method complemented by a special measuring scheme and then (b) back analysis for a given excavation shape. The method allows the simultaneous reconstruction of the stress components at the scale of excavation. A numerical simulation for a cylindrical excavation in an isotropic rock mass demonstrates the high accuracy and robustness of the method. The presence of a fractured zone surrounding the excavation can hamper the stress reconstruction, hence special measures should be taken to conduct the measurements in competent rock. 相似文献
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A. N. Galybin 《国际地质力学数值与分析法杂志》1998,22(3):175-196
The problem of the equilibrium of a plane with a circular hole and a shear crack is considered to model failure of an excavation (borehole or circular opening) in rocks weakened by discontinuities (planes of weakness). It is assumed that sliding occurs in a part of the plane of weakness when the Mohr–Coulomb friction criterion is satisfied due to the stress redistribution caused by the excavation. The method of singular integral equations is employed to solve the boundary value problem. Geomechanical problems concerning borehole breakout and rockburst caused by fault-opening interaction are discussed. © 1998 John Wiley & Sons, Ltd. 相似文献
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