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Strata deformation during construction of shaft insets in weak rock
43A the best measurement strategy is to make 25 measurements on each of two perpendicular thin sections. Texture and porosity differences appear to have no effect upon precision and accuracy.
852017 On natural deformation mechanisms in the chalk Jones, M E; Bedford, J; Clayton, C J Geol Soc London V141, N4, July 1984, P675-683 The various roles of consolidation, cementation and pressure solution in the hardening of the Purbeck chalk are examined. These processes are restricted to low permeabilities so that during hardening it is necessary for the deformation to maintain permeable pathways to dissipate any excess pore fluid pressure, either by fracturing or development of open stylolites.
852018 Estimating soil moduli from drilled pier load tests Bazant, Z J J Geoteeh Engng Die ASCE VIlO, NGT9, Sept 1984, P13231341 The modulus of deformation, of sandy soils is estimated from load tests of drilled piers assuming that only the active depth lying directly under the pier base undergoes compression. The active depth is defined as the depth of the layer in which the increment of stress produced by the transmitted load is greater than a certain given fraction of the effective geostatic stress. Instrumented load tests yield the conclusion that the modulus is equal to the secant modulus of deformation as obtained from triaxial tests. The proposed method makes it possible to predict the settlement of piers at limit load using laboratory moduli determined from samples extracted from the layer underlying the pier base. An example illustrates how the settlement of axially loaded drilled piers bearing on sand can be calculated by the proposed method using the linear elastic theory as outlined by Poulos. Auth.
852019 Application of the Mohr-circle construction to problems of inhomngeneons deformation Means, W D J Struet Geol VS, N3-4, 1983, P279-286 Off-axis Mohr circles are used to represent asymmetric secondorder tensor quantities that describe deformation with homogeneous position gradients or flow with homogeneous velocity gradients. Several applications to problems of inhomogeneous deformation are explored by considering neighbouring domains A and B that are homogeneously but differently deformed or flowing. One of these applications is that non-parallel simple shear at known rates is assumed in A and B and a construction is used to find the instantaneous orientation of a compatible boundary and the spin of one domain with respect to the other.
852020 Compatibility equations and the pole to the Mohr circle Cutler, J; Elliott, D d Struet Geol V5, N3-4, 1983, P287-297 A new form of the compatibility equations is derived for large deformations. The equations show that in a continuous inhomogeneous deformation, the strain gradients are related to the curvatures of the principal strain trajectories. In the case of uniform area strain, the equations express a direct relationship between the shape of the strain ellipse at a point and the curvatures of the principal trajectories. The pole of the finite strain Mohr circle is a unique point which relates the state of strain in the body to its orientation in the physical plane. The curve connecting the poles of a set of Mohr circles describing an inhomogeneous state of strain is called the pole curve. For some
special cases, this pole curve describes the state of strain everywh~re in a deformed cross-section.
852021 Shear bands, crenulutions and differentiated layering in icemica models Wilson, C J L J Struet Geol V6, N3, 1984, P303-319 Thin sheets of composite ice-mica were deformed in order to simulate the development of cleavages in quartz-mica rocks. Two models are presented for the initiation, propagation and evolution of the observed crenulation versus differentiated cleavage types. These depend on mica stacking and orientation relative to the transverse properties of the sample and also on the direction of anisotropy to the XY plane of the bulk strain ellipsoid. The models invoke shear on planes of high shear strain and rotation of the shear bands and rigid mica grains into a direction approximately parallel to the bulk extension direction.
852022 Evaluation of the dynamic characteristics of sands by in-situ testing techniques (In French) Seed, H B Rev Fr Geoteeh N23, 1983, P91-99 Relationships are proposed for the evaluation of the dynamic properties of sands by several in situ tests including: (1) liquefaction resistance from Standard Penetration Test (SPT) data, (2) liquefaction resistance from Cone Penetration Test (CPT) data, (3) liquefaction resistance from shear wave velocity data and (4) wave velocity and shear modulus from SPT data. It is concluded that the best defined relationship is that between liquefaction characteristics and SPT.
852023 Laboratory and theoretical study for the behaviour of a fracture under normal stress (In French) Billaux, D; Feuga, B; Gentier, S Rev Fr Geoteeh N26, 1984, P21-29 The theoretical model developed assumes that the fracture is formed of asperities of various lengths. These are assumed to have an elastic plastic behaviour and their failure criterion takes into account the confining pressure. Simple laboratory compression tests on natural fractures confirm the validity of the model.
852024 Dilatancy of rocks (In French) Sirieys, P Rev Fr Geoteeh N27, 1984, P23-25 The dilatant behaviour of brittle rocks resulting from microcracks is analysed.
852025 Strata deformation during construction of shaft insets in weak rook Shelton, P D; Farmer, I W Trans Inst Min Metali (Sect A Min lnd) V93, July 1984, P105-114 At Stillingfleet and Riccall mines in the Selby Coalfield, UK, carcase deformations and lining strains were monitored during construction of shaft insets. A study was conducted to determine the influence of rock behaviour and construction techniques on inset performance. Magnitudes of pre-lining deformation and post-construction stresses were dependent on the position of the lining relative to the face support.
852017 On natural deformation mechanisms in the chalk Jones, M E; Bedford, J; Clayton, C J Geol Soc London V141, N4, July 1984, P675-683 The various roles of consolidation, cementation and pressure solution in the hardening of the Purbeck chalk are examined. These processes are restricted to low permeabilities so that during hardening it is necessary for the deformation to maintain permeable pathways to dissipate any excess pore fluid pressure, either by fracturing or development of open stylolites.
852018 Estimating soil moduli from drilled pier load tests Bazant, Z J J Geoteeh Engng Die ASCE VIlO, NGT9, Sept 1984, P13231341 The modulus of deformation, of sandy soils is estimated from load tests of drilled piers assuming that only the active depth lying directly under the pier base undergoes compression. The active depth is defined as the depth of the layer in which the increment of stress produced by the transmitted load is greater than a certain given fraction of the effective geostatic stress. Instrumented load tests yield the conclusion that the modulus is equal to the secant modulus of deformation as obtained from triaxial tests. The proposed method makes it possible to predict the settlement of piers at limit load using laboratory moduli determined from samples extracted from the layer underlying the pier base. An example illustrates how the settlement of axially loaded drilled piers bearing on sand can be calculated by the proposed method using the linear elastic theory as outlined by Poulos. Auth.
852019 Application of the Mohr-circle construction to problems of inhomngeneons deformation Means, W D J Struet Geol VS, N3-4, 1983, P279-286 Off-axis Mohr circles are used to represent asymmetric secondorder tensor quantities that describe deformation with homogeneous position gradients or flow with homogeneous velocity gradients. Several applications to problems of inhomogeneous deformation are explored by considering neighbouring domains A and B that are homogeneously but differently deformed or flowing. One of these applications is that non-parallel simple shear at known rates is assumed in A and B and a construction is used to find the instantaneous orientation of a compatible boundary and the spin of one domain with respect to the other.
852020 Compatibility equations and the pole to the Mohr circle Cutler, J; Elliott, D d Struet Geol V5, N3-4, 1983, P287-297 A new form of the compatibility equations is derived for large deformations. The equations show that in a continuous inhomogeneous deformation, the strain gradients are related to the curvatures of the principal strain trajectories. In the case of uniform area strain, the equations express a direct relationship between the shape of the strain ellipse at a point and the curvatures of the principal trajectories. The pole of the finite strain Mohr circle is a unique point which relates the state of strain in the body to its orientation in the physical plane. The curve connecting the poles of a set of Mohr circles describing an inhomogeneous state of strain is called the pole curve. For some
special cases, this pole curve describes the state of strain everywh~re in a deformed cross-section.
852021 Shear bands, crenulutions and differentiated layering in icemica models Wilson, C J L J Struet Geol V6, N3, 1984, P303-319 Thin sheets of composite ice-mica were deformed in order to simulate the development of cleavages in quartz-mica rocks. Two models are presented for the initiation, propagation and evolution of the observed crenulation versus differentiated cleavage types. These depend on mica stacking and orientation relative to the transverse properties of the sample and also on the direction of anisotropy to the XY plane of the bulk strain ellipsoid. The models invoke shear on planes of high shear strain and rotation of the shear bands and rigid mica grains into a direction approximately parallel to the bulk extension direction.
852022 Evaluation of the dynamic characteristics of sands by in-situ testing techniques (In French) Seed, H B Rev Fr Geoteeh N23, 1983, P91-99 Relationships are proposed for the evaluation of the dynamic properties of sands by several in situ tests including: (1) liquefaction resistance from Standard Penetration Test (SPT) data, (2) liquefaction resistance from Cone Penetration Test (CPT) data, (3) liquefaction resistance from shear wave velocity data and (4) wave velocity and shear modulus from SPT data. It is concluded that the best defined relationship is that between liquefaction characteristics and SPT.
852023 Laboratory and theoretical study for the behaviour of a fracture under normal stress (In French) Billaux, D; Feuga, B; Gentier, S Rev Fr Geoteeh N26, 1984, P21-29 The theoretical model developed assumes that the fracture is formed of asperities of various lengths. These are assumed to have an elastic plastic behaviour and their failure criterion takes into account the confining pressure. Simple laboratory compression tests on natural fractures confirm the validity of the model.
852024 Dilatancy of rocks (In French) Sirieys, P Rev Fr Geoteeh N27, 1984, P23-25 The dilatant behaviour of brittle rocks resulting from microcracks is analysed.
852025 Strata deformation during construction of shaft insets in weak rook Shelton, P D; Farmer, I W Trans Inst Min Metali (Sect A Min lnd) V93, July 1984, P105-114 At Stillingfleet and Riccall mines in the Selby Coalfield, UK, carcase deformations and lining strains were monitored during construction of shaft insets. A study was conducted to determine the influence of rock behaviour and construction techniques on inset performance. Magnitudes of pre-lining deformation and post-construction stresses were dependent on the position of the lining relative to the face support.