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Two-dimensional simulation of geotechnical problems based on solid modeling
ANALYSIS TECHNIQUES:DESIGN METHODS The use of numerical models, that incorporate sophisticated numerical techniques, is becoming a part of modern geotechnical engineering design. Such models are expected to simulate the field behavior considerably better than conventional methods. However, they need large capacity computers. On the other hand, the proposed analytical model is simpler and needs small capacity computers to provide aid for preliminary designs. Site problems may be evaluated on the spot without running a highly sophisticated, time consuming and costly finite element program, i.e. the structure can be back-analyzed using the measured deformed shape. This study also includes comparison of results of this simple model with actual field measurements and results of sophisticated finite element analyses. (Author)
953113 Two-dimensional simulation of geotechnieal problems based on solid modeling L. F. Martha, S. A. B. Da Fontoura & P. C. P. Carvalho, in:
Applications of computational mechanics in geotechnical engineering. Prec. workshop, Rio de Janeiro, 1991, ed E.A. Vargas & & others, (Balkema), 1994, pp 403-420. The paper describes the use of topological data structures underlying interactive graphics geomechanics simulation systems related to planar subdivisions. This approach is adopted in a finite element system for underground mining excavation and in a program for balancing geological crosssections. The geometric information is coupled with the adjacency information provided by the topological data structure in a solid modeling approach. The result is an intelligent graphical simulator, which is capable of recognizing adjacency relationships among the regions of a subdivision and enforcing their consistency. (Authors)
953114 New techniques to aid interactive graphical finite element analysis M. Gattass & C.H. Levy, in: Applications of computational mechanics in geotechnical engineering. Prec. workshop, Rio de Janeiro, 1991, ed E.A. Vargas & & others, (llalkema), 1994, pp 453-463. This work discusses new disciplines that are important to the development of interactive graphical finite element analysis programs. After a brief presentation of the disciplines related to the development of this type of program, the paper focuses on user interface isues. These issues are discussed from both the application programmer's and the user's point of view. (Authors)
953115 Error estimates and adaptive procedures in geotechnieal problems J. Almeida e Sousa, L. Ribeiro e Sousa & V. S. Violante, in:
Applications of computational mechanics in geoteehnical engineering. Prec. workshop, Rio de Janeiro, 1991, ed E.A. Vargas & & others, (llalkema), 1994, pp 353-370. The success in using finite element models for geotechnical problems is highly dependent on the diseretization that is used, therefore it is very important to estimate the error resulting from the discretization. This work presents several procedures for error estimates and techniques developed for the adaptive refinement of the meshes. An adaptive finite element model using the h method by refining the successive meshes was developed, and some studies of application of this model are presented, referring to the error analyses and to the analysis of an underground hydroelectric powerhouse. (Authors) RMMS 32:3--H
119A
953116 The hybrid boundary element method: an efficient tool for dealing with geotechnical problems N. A. Dumont, in: Applications of computational mechanics
in geotechnical engineering. Prec. workshop, Rio de Janeiro, 1991, ed E.A. Vargas & & others, (Balkema), 1994, pp 421438. The most important features of a new numerical method are outlined. The mechanical, or variational consistency of the hybrid finite element method is extended to the conventional boundary element formulation, giving rise to naturally established symmetric force-displacement relations. The computational effort for the complete solution of a given problem, according to this method, is in some cases only a small fraction of the effort needed with traditional methods. This paper also outlines briefly the types of analyses which may be advantageously performed with this new method, many of which are already being implemented by the author and co-workers. Some numerical examples are provided. (Author) 953117 Elasto-plastic finite element analyses of a braced excavation and a tunnel R. F. Azevedo, A. B. Parreira & J. G. Zornberg, in:
Applications of computational mechanics in geotechnical engineering. Prec. workshop, Rio de Janeiro, 1991, ed E.A. Vargas & & others, (Balkema), 1994, pp 255-273. This paper deals with the numerical analyses of an excavation and a tunnel built during the construction of Sao Panlo city metropolitan. The excavation was made with a retaining system that consisted of soldier piles with lagging, whereas the tunnel was constructed by the New Austrian Tunneling Method (NATM). Initially, the paper presents the computer program developed for the analyses and the geotechnical laboratory properties of the soils involved in the constructions. Subsequently, using the new program and the geotechnical properties, elasto-plastic solutions for the excavation and the tunnel are obtained and some displacements observed by the field instrumentation during the tunnel construction are compared with the analytical results. At the end, some conclusions are drawn, basically mentioning that the elasto-plastic solutions were very promising and compared well with the observed field results. (Authors)
953118 Behaviour of a shallow tunnel in granite residual soils J. Almeida e Sousa, A. S. Cardoso, M. M. Fernandes & L. Ribeiro e Sousa, in: Applications of computational mechanics in geotechnical engineering. Prec. workshop, Rio de Janeiro, 1991, ed E.A. Vargas & & others, (Balkema), 1994, pp 243253. This paper presents the results of the application of 2D and 3D finite element models to a railway tunnel excavated in granite residual soils in the north of Portugal. A brief description of the work and monitoring system is included and the results of the observation are compared with those calculated numerically. (Authors) 953119 Limit analysis of geotechnicai problems U E. Vaz, P. O. Faria & E. A. Vargas, in: Applications of computational mechanics in geotechnical engineering. Prec. workshop, Rio de Janeiro, 1991, ed E.A. Vargas & & others, (Balkema), 1994, pp 385-401. This paper presents mathematical models for the determination of the collapse load in geotechnical bidimensional problems. The formulation is based on the limit analysis theorems of the plasticity theory. For the continuous media the finite element method is used in order to discretize the problem and for the discontinuous media the method of
953113 Two-dimensional simulation of geotechnieal problems based on solid modeling L. F. Martha, S. A. B. Da Fontoura & P. C. P. Carvalho, in:
Applications of computational mechanics in geotechnical engineering. Prec. workshop, Rio de Janeiro, 1991, ed E.A. Vargas & & others, (Balkema), 1994, pp 403-420. The paper describes the use of topological data structures underlying interactive graphics geomechanics simulation systems related to planar subdivisions. This approach is adopted in a finite element system for underground mining excavation and in a program for balancing geological crosssections. The geometric information is coupled with the adjacency information provided by the topological data structure in a solid modeling approach. The result is an intelligent graphical simulator, which is capable of recognizing adjacency relationships among the regions of a subdivision and enforcing their consistency. (Authors)
953114 New techniques to aid interactive graphical finite element analysis M. Gattass & C.H. Levy, in: Applications of computational mechanics in geotechnical engineering. Prec. workshop, Rio de Janeiro, 1991, ed E.A. Vargas & & others, (llalkema), 1994, pp 453-463. This work discusses new disciplines that are important to the development of interactive graphical finite element analysis programs. After a brief presentation of the disciplines related to the development of this type of program, the paper focuses on user interface isues. These issues are discussed from both the application programmer's and the user's point of view. (Authors)
953115 Error estimates and adaptive procedures in geotechnieal problems J. Almeida e Sousa, L. Ribeiro e Sousa & V. S. Violante, in:
Applications of computational mechanics in geoteehnical engineering. Prec. workshop, Rio de Janeiro, 1991, ed E.A. Vargas & & others, (llalkema), 1994, pp 353-370. The success in using finite element models for geotechnical problems is highly dependent on the diseretization that is used, therefore it is very important to estimate the error resulting from the discretization. This work presents several procedures for error estimates and techniques developed for the adaptive refinement of the meshes. An adaptive finite element model using the h method by refining the successive meshes was developed, and some studies of application of this model are presented, referring to the error analyses and to the analysis of an underground hydroelectric powerhouse. (Authors) RMMS 32:3--H
119A
953116 The hybrid boundary element method: an efficient tool for dealing with geotechnical problems N. A. Dumont, in: Applications of computational mechanics
in geotechnical engineering. Prec. workshop, Rio de Janeiro, 1991, ed E.A. Vargas & & others, (Balkema), 1994, pp 421438. The most important features of a new numerical method are outlined. The mechanical, or variational consistency of the hybrid finite element method is extended to the conventional boundary element formulation, giving rise to naturally established symmetric force-displacement relations. The computational effort for the complete solution of a given problem, according to this method, is in some cases only a small fraction of the effort needed with traditional methods. This paper also outlines briefly the types of analyses which may be advantageously performed with this new method, many of which are already being implemented by the author and co-workers. Some numerical examples are provided. (Author) 953117 Elasto-plastic finite element analyses of a braced excavation and a tunnel R. F. Azevedo, A. B. Parreira & J. G. Zornberg, in:
Applications of computational mechanics in geotechnical engineering. Prec. workshop, Rio de Janeiro, 1991, ed E.A. Vargas & & others, (Balkema), 1994, pp 255-273. This paper deals with the numerical analyses of an excavation and a tunnel built during the construction of Sao Panlo city metropolitan. The excavation was made with a retaining system that consisted of soldier piles with lagging, whereas the tunnel was constructed by the New Austrian Tunneling Method (NATM). Initially, the paper presents the computer program developed for the analyses and the geotechnical laboratory properties of the soils involved in the constructions. Subsequently, using the new program and the geotechnical properties, elasto-plastic solutions for the excavation and the tunnel are obtained and some displacements observed by the field instrumentation during the tunnel construction are compared with the analytical results. At the end, some conclusions are drawn, basically mentioning that the elasto-plastic solutions were very promising and compared well with the observed field results. (Authors)
953118 Behaviour of a shallow tunnel in granite residual soils J. Almeida e Sousa, A. S. Cardoso, M. M. Fernandes & L. Ribeiro e Sousa, in: Applications of computational mechanics in geotechnical engineering. Prec. workshop, Rio de Janeiro, 1991, ed E.A. Vargas & & others, (Balkema), 1994, pp 243253. This paper presents the results of the application of 2D and 3D finite element models to a railway tunnel excavated in granite residual soils in the north of Portugal. A brief description of the work and monitoring system is included and the results of the observation are compared with those calculated numerically. (Authors) 953119 Limit analysis of geotechnicai problems U E. Vaz, P. O. Faria & E. A. Vargas, in: Applications of computational mechanics in geotechnical engineering. Prec. workshop, Rio de Janeiro, 1991, ed E.A. Vargas & & others, (Balkema), 1994, pp 385-401. This paper presents mathematical models for the determination of the collapse load in geotechnical bidimensional problems. The formulation is based on the limit analysis theorems of the plasticity theory. For the continuous media the finite element method is used in order to discretize the problem and for the discontinuous media the method of