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Excavation of galleries in deep clay formations: an analytical tool for the control of finite element results
36A
UNDERGROUND EXCAVATIONS:OPENING STRESS
structure is also carried out. It is shown that the HD-LRB system significantly reduces the mean-square, as well as the peak acceleration and deflection responses without generating large base displacements. Furthermore, the non-linear behaviour of the HD-LRB somewhat improves the performance of the bearing in reducing the peak responses of the secondary system and the primary structure when compared with the linear LRB model. (from Authors)
951260 Pseudedynamic testing of strain-softening systems with adaptive time steps O. S. Bursi, Pui-Shum B. Shing & Z. Radakovic-Guzina, Earthquake Engineering & Structural Dynamics, 23(7), 1994, pp 745-760. A structure may exhibit a severe strain-softening behaviour when subjected to strong earthquake excitation. Pseudodynamic testing of such structures using an implicit timeintegration algorithm may be conceived of as a problem, since the Newton-type iterations, which are often required when structural non-linearity develops, may not converge under these circumstances. An unconditionally stable implicit timeintegration algorithm implemented with Newton-type iterations is analysed to provide an insight into this problem. A simple convergence condition is derived to detect possible divergence. The condition is shown to be a sufficient criterion for convergence for general multiple-degree-of-freedom structures, and it is used to develop an adaptive timestepping strategy to avoid divergence under severe strainsoftening conditions. (from Authors)
951261 An inelastic substructure technique for the pseudodynamic test method S. P. Schneider & C. W. Roeder, Earthquake Engineering & Structural Dynamics, 23(7), 1994, pp 761-775. An inelastic substructure technique for the pseudodynamic test method is described. This technique requires testing of only a critical component of a multi-degree-of-freedom structure, while the remaining portion is modelled using standard inelastic analytical procedures. This paper describes the development of a substructure algorithm which is verified with a numerically s~aulated test. (from Authors)
951262 Inelastic seismic response of torsionally unbalanced systems designed using elastic dynamic analysis C. M. Wong & W. K. Tso, Earthquake Engineering & Structural Dynamics, 23(7), 1994, pp 777-798. This paper evaluates the inelastic seismic response of torsionally unbalanced structural systems with strength distributed using elastic response spectrum analysis. It is shown that the inelastic responses depend strongly on the torsional stiffness of the system. For a torsionally stiff system, the torsional response leads to a decrease in the stiff edge displacement; however, for a torsionally flexible system, it tends to increase the stiff edge displacement. With accidental torsion effect incorporated, the response spectrum analysis will give a strength distribution such that there will be no excessive additional ductility demands on the lateral load resisting elements. (from Authors)
951263 Seismic rnndom-vibration analysis of multisupport-strucrural systems E. Heredia-Zavoni & E. H. Vanmarcke, Journal of Engineering Mechanics - ASCE, 120(5), 1994, pp 1107-1128.
A random-vibration methodology is formulated for the seismic-response analysis of linear multisupport-structural systems. It reduces the response evaluation to that of a series of linear one-degree systems in a way that fully accounts for the multiple-support input and the space-time correlation structure of the ground motion. Three spectral parameters are introduced and interpreted in terms of cross-correlation coefficients and spectral moments associated with the response of one-degree systems. The influence of localspatial variation of ground motion on the spectral parameters is also studied. (Authors)
951264 Analysis of embedded foundations by substructure-deletion method R. Betti & A. M. Abdel-Ghaffar, Journal of Engineering Mechanics - ASCE, 120(6), 1994, pp 1283-1303. An alternative formulation of the substructure-deletion method for the dynamic analysis of thrce-dimensional embedded foundations of arbitrary shape subjected to applied external forces and to incoming seismic waves is presented. The analysis is performed in the frequency domain, and the foundations are assumed to be rigid and embedded in a homogeneous viscoelastic half-space, with welded contact along the embedded surface. This new formulation of the substructure-deletion method is characterized by a boundaryintegral approach for the analysis of the removed soil inclusion, using Green's functions for an infinite viscoelastic medium, while half-space Green's functions are applied in the analysis of the fiat half-space. (from Authors)
951265 Seismic shear demand of ductile cantilever walls: a Canadian code perspective A. Filiatrault, D. D'Aronco & R. Tinawi, Canadian Journal of Civil Engineering, 21(3), 1994, pp 363-376. During severe earthquakes, ductile flexural walls are expected to exhibit inelastic flexural behaviour while other brittle deformation mechanisms, such as shear, should remain elastic. The philosophy of the Canadian seismic provisions for flexural walls is based on the assumption that the force reduction factor is applicable to both flexure and shear. If the bended moments are limited because of the flexural strength of a wall, then the shear forces are considered to be limited by the same ratio. Brittle shear failures in walls are still possible even if their shear strengths are established by the Canadian standards. This paper presents an analytical investigation on the shear demand of ductile flexural walls designed for three different seismic zones in Canada. (from Authors)
UNDERGROUND EXCAVATIONS Stresses around underground openings 951266 Excavation of gaHerles in deep clay formations: an analytical tool for the control of finite element results D. J. De Bruyn, C. C. Ramaeckers & P. J. Huergo, Computers & Geotechnics, 16(3), 1994, pp 247-260. The equations of pressure and displacement equilibrium in an elastic perfectly plastic medium are presented for both spherical and cylindrical symmetry. The excavation of a gallery in a deep clay formation is then modelled and the displacements behind the tunnel face may be estimated. Numerical simulations are compared to field data; within the limitation of the hypotheses taken into account, the compar-
U N D E R G R O U N D EXCAVATIONS:TUNNELS ison is fair. The equations presented and the associated results may provide a benchmark test for finite element or boundary element computer codes written for the same purpose. (from Authors) 951267 Earth pressmre on a block pumphouse of the Zaporozh'e nuclear power plant E. N. Bellendir, A. L. Gol'din & A. A. Gotlif, Soil Mechanics & Foundation Engineering, 31(1), 1994, pp 1219; translated from: Osnovaniya, Fundamenty i M e k h a n i k a Gruntov, no.l, 1994, pp 10-15. Results are set forth from a set of investigations (full-scale observations, laboratory experiments, and calculations by the finite-element method) to determine the lateral earth pressure on the underground part of a block pumphouse of the Zaporozh'e nuclear power plant. Laboratory investigations of sandy soils made it possible to confirm the validity of basic premises of a model of nonassociated plasticity and suggest a procedure for determining the model's parameters. Comparison of the results of FEM calculations with data from fullscale observations showed that satisfactory correspondence is achieved only by taking into account strengthening and the sequence of erection of the structure and backfilling. (Journal summary)
Tunnels 951268 TML France: the civil engineering work for the Channel Tunnel in France P. Matheron, Proceedings - ICE: Civil Engineering - the Channel Tunnel, Part 3, 1994, pp 3-5. The construction director for the French section of the £10 billion Channel Tunnel project introduces this Special Issue by describing how the French construction work was organized, how the decentralized management met its objectives and how effective communication with up to 4000 site staff was maintained throughout the six-year construction programme. (Author) 951269
Tunnels - geology H. Barthcs & 12 others, Proceedings - ICE: Civil Engineering - the Channel Tunnel, Part 3, 1994, pp 6-10. In 1882, the geology of the Pas-de-Calais region was investigated in connection with a Channel crossing project. After an historical review of these surveys, this paper describes subsequent exploratory work carried out after the submission and study by means of the geostatic method and the geological data, and the presence of Chalk Marl. A description of the geotechnicai characteristics and the tectonics of the site is followed by a section on the choice of the alignment based upon these data. The paper concludes with a detailed description of the geological follow-up studies carried out during the works. (Authors) 951270
Tunnels - transport logistics H. Barthes & 12 others, Proceedings - ICE: Civil Engineering - the Channel Tunnel, Part 3, 1994, pp 11-14. The paper opens with a description of the constraints imposed by a tunnel project. The organization of train deliveries using rails in the tunnels, for the transport of personnel as well as equipment is detailed, and the techniques employed in the removal of spoil, including pumping, are outlined in the final paragraphs. (Authors)
37A
951271 Tunnels tunnel boring machines H. Barthes & 12 others, Proceedings - ICE: Civil Engineering the Channel Tunnel, Part 3, 1994, pp 15-19. -
-
This paper begins by describing the requirements for the tunnelling machines. Five machines were used, three on the marine tunnels and two on the land tunnels. The description is then developed, distinguishing between the types of machines working under the sea and those under land. A table summarizes the main characteristics of the tunnelling machines. (Authors) 951272 Tunnels - electric power supply H. Barthes & 12 others, Proceedings - ICE: Civil Engineering - the Channel Tunnel, Part 3, 1994, pp 20-22. Almost all the power consumed by the Channel Tunnel project (98%) was electrical. This energy was provided by the Gravelines nuclear power plant, backed where necessary by the Palnel nuclear plant. On the site, electric power was distributed by three ring-main circuits. The main functions on the underground sites were clearly differentiated and the power circuits were doubled to ensure the dependability of the network. Finally, a stand-by power plant using diesel engines was provided to supply 8500 kW when necessary. (Authors) 951273 Tunnels - the Fond-Pignon discharge site H. Barthes & 12 others, Proceedings - ICE: Civil Engineering - the Channel Tunnel, Part 3, 1994, pp 23-25. The natural basin of Fond-Pignon, about 2 km from the Sangatte shaft, was chosen as the discharge site for tunnelling spoil. It was therefore necessary to build an embankment across the basin. This paper describes the embankment and its retaining capacities and discusses the characteristics and consolidation process of the spoil, which was pumped from the shaft as a slurry. (Authors) 951274 Tunnels - dcwatering H. Barthes & 12 others, Proceedings- ICE: Civil Engineering - the Channel Tunnel, Part 3, 1994, pp 26-29. Three muses of water ingress were taken into account during the driving phases: lining leakage rates, normal and accidental water inflows related to the excavation sites, and the residue of service water used in tunnels. This paper reviews these assumptions and then describes the dewatering installations at the Sangatte shaft, in both the land and marine tunnels. (Authors) 951275 Tunnels - ventilation H. Barthes & 12 others, Proceedings - ICE: Civil Engineering - the Channel Tunnel, Part 3, 1994, pp 30-33. Ventilation requirements were evaluated in accordance with the regulations and recommendations of the social security organization, the building and public works safety organization, the underground works association and the underground mine regulations. This paper describes the equipment chosen for the marine and land tunnelling operations and explains how ventilation arrangements changed as the work progressed. (Authors) 951276
Tunnels - shaft and marshalling chambers H. Bartbes & 12 others, Proceedings- ICE: Civil Engineering - the Channel Tunnel, Part 3, 1994, pp 34-38.
UNDERGROUND EXCAVATIONS:OPENING STRESS
structure is also carried out. It is shown that the HD-LRB system significantly reduces the mean-square, as well as the peak acceleration and deflection responses without generating large base displacements. Furthermore, the non-linear behaviour of the HD-LRB somewhat improves the performance of the bearing in reducing the peak responses of the secondary system and the primary structure when compared with the linear LRB model. (from Authors)
951260 Pseudedynamic testing of strain-softening systems with adaptive time steps O. S. Bursi, Pui-Shum B. Shing & Z. Radakovic-Guzina, Earthquake Engineering & Structural Dynamics, 23(7), 1994, pp 745-760. A structure may exhibit a severe strain-softening behaviour when subjected to strong earthquake excitation. Pseudodynamic testing of such structures using an implicit timeintegration algorithm may be conceived of as a problem, since the Newton-type iterations, which are often required when structural non-linearity develops, may not converge under these circumstances. An unconditionally stable implicit timeintegration algorithm implemented with Newton-type iterations is analysed to provide an insight into this problem. A simple convergence condition is derived to detect possible divergence. The condition is shown to be a sufficient criterion for convergence for general multiple-degree-of-freedom structures, and it is used to develop an adaptive timestepping strategy to avoid divergence under severe strainsoftening conditions. (from Authors)
951261 An inelastic substructure technique for the pseudodynamic test method S. P. Schneider & C. W. Roeder, Earthquake Engineering & Structural Dynamics, 23(7), 1994, pp 761-775. An inelastic substructure technique for the pseudodynamic test method is described. This technique requires testing of only a critical component of a multi-degree-of-freedom structure, while the remaining portion is modelled using standard inelastic analytical procedures. This paper describes the development of a substructure algorithm which is verified with a numerically s~aulated test. (from Authors)
951262 Inelastic seismic response of torsionally unbalanced systems designed using elastic dynamic analysis C. M. Wong & W. K. Tso, Earthquake Engineering & Structural Dynamics, 23(7), 1994, pp 777-798. This paper evaluates the inelastic seismic response of torsionally unbalanced structural systems with strength distributed using elastic response spectrum analysis. It is shown that the inelastic responses depend strongly on the torsional stiffness of the system. For a torsionally stiff system, the torsional response leads to a decrease in the stiff edge displacement; however, for a torsionally flexible system, it tends to increase the stiff edge displacement. With accidental torsion effect incorporated, the response spectrum analysis will give a strength distribution such that there will be no excessive additional ductility demands on the lateral load resisting elements. (from Authors)
951263 Seismic rnndom-vibration analysis of multisupport-strucrural systems E. Heredia-Zavoni & E. H. Vanmarcke, Journal of Engineering Mechanics - ASCE, 120(5), 1994, pp 1107-1128.
A random-vibration methodology is formulated for the seismic-response analysis of linear multisupport-structural systems. It reduces the response evaluation to that of a series of linear one-degree systems in a way that fully accounts for the multiple-support input and the space-time correlation structure of the ground motion. Three spectral parameters are introduced and interpreted in terms of cross-correlation coefficients and spectral moments associated with the response of one-degree systems. The influence of localspatial variation of ground motion on the spectral parameters is also studied. (Authors)
951264 Analysis of embedded foundations by substructure-deletion method R. Betti & A. M. Abdel-Ghaffar, Journal of Engineering Mechanics - ASCE, 120(6), 1994, pp 1283-1303. An alternative formulation of the substructure-deletion method for the dynamic analysis of thrce-dimensional embedded foundations of arbitrary shape subjected to applied external forces and to incoming seismic waves is presented. The analysis is performed in the frequency domain, and the foundations are assumed to be rigid and embedded in a homogeneous viscoelastic half-space, with welded contact along the embedded surface. This new formulation of the substructure-deletion method is characterized by a boundaryintegral approach for the analysis of the removed soil inclusion, using Green's functions for an infinite viscoelastic medium, while half-space Green's functions are applied in the analysis of the fiat half-space. (from Authors)
951265 Seismic shear demand of ductile cantilever walls: a Canadian code perspective A. Filiatrault, D. D'Aronco & R. Tinawi, Canadian Journal of Civil Engineering, 21(3), 1994, pp 363-376. During severe earthquakes, ductile flexural walls are expected to exhibit inelastic flexural behaviour while other brittle deformation mechanisms, such as shear, should remain elastic. The philosophy of the Canadian seismic provisions for flexural walls is based on the assumption that the force reduction factor is applicable to both flexure and shear. If the bended moments are limited because of the flexural strength of a wall, then the shear forces are considered to be limited by the same ratio. Brittle shear failures in walls are still possible even if their shear strengths are established by the Canadian standards. This paper presents an analytical investigation on the shear demand of ductile flexural walls designed for three different seismic zones in Canada. (from Authors)
UNDERGROUND EXCAVATIONS Stresses around underground openings 951266 Excavation of gaHerles in deep clay formations: an analytical tool for the control of finite element results D. J. De Bruyn, C. C. Ramaeckers & P. J. Huergo, Computers & Geotechnics, 16(3), 1994, pp 247-260. The equations of pressure and displacement equilibrium in an elastic perfectly plastic medium are presented for both spherical and cylindrical symmetry. The excavation of a gallery in a deep clay formation is then modelled and the displacements behind the tunnel face may be estimated. Numerical simulations are compared to field data; within the limitation of the hypotheses taken into account, the compar-
U N D E R G R O U N D EXCAVATIONS:TUNNELS ison is fair. The equations presented and the associated results may provide a benchmark test for finite element or boundary element computer codes written for the same purpose. (from Authors) 951267 Earth pressmre on a block pumphouse of the Zaporozh'e nuclear power plant E. N. Bellendir, A. L. Gol'din & A. A. Gotlif, Soil Mechanics & Foundation Engineering, 31(1), 1994, pp 1219; translated from: Osnovaniya, Fundamenty i M e k h a n i k a Gruntov, no.l, 1994, pp 10-15. Results are set forth from a set of investigations (full-scale observations, laboratory experiments, and calculations by the finite-element method) to determine the lateral earth pressure on the underground part of a block pumphouse of the Zaporozh'e nuclear power plant. Laboratory investigations of sandy soils made it possible to confirm the validity of basic premises of a model of nonassociated plasticity and suggest a procedure for determining the model's parameters. Comparison of the results of FEM calculations with data from fullscale observations showed that satisfactory correspondence is achieved only by taking into account strengthening and the sequence of erection of the structure and backfilling. (Journal summary)
Tunnels 951268 TML France: the civil engineering work for the Channel Tunnel in France P. Matheron, Proceedings - ICE: Civil Engineering - the Channel Tunnel, Part 3, 1994, pp 3-5. The construction director for the French section of the £10 billion Channel Tunnel project introduces this Special Issue by describing how the French construction work was organized, how the decentralized management met its objectives and how effective communication with up to 4000 site staff was maintained throughout the six-year construction programme. (Author) 951269
Tunnels - geology H. Barthcs & 12 others, Proceedings - ICE: Civil Engineering - the Channel Tunnel, Part 3, 1994, pp 6-10. In 1882, the geology of the Pas-de-Calais region was investigated in connection with a Channel crossing project. After an historical review of these surveys, this paper describes subsequent exploratory work carried out after the submission and study by means of the geostatic method and the geological data, and the presence of Chalk Marl. A description of the geotechnicai characteristics and the tectonics of the site is followed by a section on the choice of the alignment based upon these data. The paper concludes with a detailed description of the geological follow-up studies carried out during the works. (Authors) 951270
Tunnels - transport logistics H. Barthes & 12 others, Proceedings - ICE: Civil Engineering - the Channel Tunnel, Part 3, 1994, pp 11-14. The paper opens with a description of the constraints imposed by a tunnel project. The organization of train deliveries using rails in the tunnels, for the transport of personnel as well as equipment is detailed, and the techniques employed in the removal of spoil, including pumping, are outlined in the final paragraphs. (Authors)
37A
951271 Tunnels tunnel boring machines H. Barthes & 12 others, Proceedings - ICE: Civil Engineering the Channel Tunnel, Part 3, 1994, pp 15-19. -
-
This paper begins by describing the requirements for the tunnelling machines. Five machines were used, three on the marine tunnels and two on the land tunnels. The description is then developed, distinguishing between the types of machines working under the sea and those under land. A table summarizes the main characteristics of the tunnelling machines. (Authors) 951272 Tunnels - electric power supply H. Barthes & 12 others, Proceedings - ICE: Civil Engineering - the Channel Tunnel, Part 3, 1994, pp 20-22. Almost all the power consumed by the Channel Tunnel project (98%) was electrical. This energy was provided by the Gravelines nuclear power plant, backed where necessary by the Palnel nuclear plant. On the site, electric power was distributed by three ring-main circuits. The main functions on the underground sites were clearly differentiated and the power circuits were doubled to ensure the dependability of the network. Finally, a stand-by power plant using diesel engines was provided to supply 8500 kW when necessary. (Authors) 951273 Tunnels - the Fond-Pignon discharge site H. Barthes & 12 others, Proceedings - ICE: Civil Engineering - the Channel Tunnel, Part 3, 1994, pp 23-25. The natural basin of Fond-Pignon, about 2 km from the Sangatte shaft, was chosen as the discharge site for tunnelling spoil. It was therefore necessary to build an embankment across the basin. This paper describes the embankment and its retaining capacities and discusses the characteristics and consolidation process of the spoil, which was pumped from the shaft as a slurry. (Authors) 951274 Tunnels - dcwatering H. Barthes & 12 others, Proceedings- ICE: Civil Engineering - the Channel Tunnel, Part 3, 1994, pp 26-29. Three muses of water ingress were taken into account during the driving phases: lining leakage rates, normal and accidental water inflows related to the excavation sites, and the residue of service water used in tunnels. This paper reviews these assumptions and then describes the dewatering installations at the Sangatte shaft, in both the land and marine tunnels. (Authors) 951275 Tunnels - ventilation H. Barthes & 12 others, Proceedings - ICE: Civil Engineering - the Channel Tunnel, Part 3, 1994, pp 30-33. Ventilation requirements were evaluated in accordance with the regulations and recommendations of the social security organization, the building and public works safety organization, the underground works association and the underground mine regulations. This paper describes the equipment chosen for the marine and land tunnelling operations and explains how ventilation arrangements changed as the work progressed. (Authors) 951276
Tunnels - shaft and marshalling chambers H. Bartbes & 12 others, Proceedings- ICE: Civil Engineering - the Channel Tunnel, Part 3, 1994, pp 34-38.