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Note on the conductivity of electrolytes for analog models. Technical note
1A
Geomechanics Abstracts
General 831001 GEOLOGY, GEGMORPHOLOGY AND GEOTECHNICS Henkel, D J Geotechnique, V32, N3, Sept 1982, P175-19~ The Importamce of collaboration between geologists and geotechnlcal englneera is emphasized and the cocoon ~nterest ~L geomor!~Olo~r is suggested as a useful llnk to enable both the geological engineering skills to be mobilized. The role of geccorphology in the ~mderstar~ling of soil movements in the Gulf of Mexico during hurricanes is discussed. Attention is dra~n to problems of tropical weathering a~i char~es in soil chemistry which need further study. Some of the problems associated with grou~water lowering in an area underlain by dolomite are described together with the effects on stability of ~zlnor changes in surface dralr~ge of an inclined rock layer. Auth. 831002 RESPONSE CHAPACT~ERI~IqCS OF CYLINDRICAL PIEZGM~S Brand, E W; Premchitt, J Geotechnique, V32, N3, Sept 1982, P203-216 Finite difference solutiorm are presented for the fund~ental process of pore pressure equalization in a soil-plezometer system for cylindrical piezometers. The response-tlme relationships established for cylindrical piezometers are of the same general form as those for spherical piezometers, the exact shape of a particular relationship being a fumction of the piezometer ~roportions, the soll coml~resslbillty and the flexibility of the piezometer measuring system. The cylindrical equalization chart is constructed, which provides a direct means for the analysis of equalization tests in cylindrical piezometers. Interpretation of laboratory tests on piezometers embedded in clay triaxial specimens shows that equalization tests can provide reliable in situ measurements of soil permeability and good estimations of coefficients of consolidation. 831003 NOTE ON THE C O N D U C T M T Y OF EI~CTROLYTES FOR ANALOG MODELS. TECHNICAL NOTE Brand, E W; Premchltt, J Geotech Test J, V4, N3, Sept 1981, P123-125 Durirg the measurement of piezometer shape factors using a liquid electric analog model (consisting of a tank containing an electrolyte ), it was found that the electrolyte resistance was temperature dependent. A study of temperature effects showed that the conductivity of ~ater varied by only 1. 9 per cent per deg C, compared to almost twice as much for cop~er sulphate solution. It was concluded • that tap water was the more suitable electrolyte to achieve accurate measurements of piezometer shape factors.
831004 ON PHYSICAL MODELLING OF ROCK Cheney, J A Geol~hYs Res Lett, vS, NT, July 1981, P719-720 The problems of satisfying similarity between a physical model and the prototype in rock wherein fissures and cracks play a role in ~ s i c a l behaviour is explored. The need for models of large l~hysical dimensions is explained b~t also reefing of models of the same prototype over a wide range of scales is needed to ascertain the influence of lack of slmilitu~e of particular parameters between prototype and model. A large capacity centrifuge would be useful in that respect. Auth. 831005 SIMPLE AND EFFICIENT N~THOD F ~ INI~ODUCING FAULTS INTO FINITE ELEMENT COMPUTATIONS Meloah, H J; Raefeky, A Bull Selsmol Soc Am, V71, N~, Oct 1961, P1391-1400 This paper outlines a new method, the 'split node technique' for introducing fault displacements into finite element numerical computations. The value of the displacement at a single node point shared between two elements depends upon which element it is referred to, thus introducing a displacement discontinudty between the two elements. We shc~ that the modification i~duced by this splitting can be contained in the load vector, so that the stiffness matrix is not altered. The ra~mber of degrees of freedom is not increased by splitting. This method can be implemented entirely on the local element level, ar~ we show rigorously that no net forces or moments are induced on the finite element grid when isoparametric elements are used. This method is thus of great utility in many geological and engineering applications. Auth. 831006 COMBINED METHOD FOR THE CALCULATION OF ELASTIC SOLIDS UND~R HIGH DEFORMATION (IN FRENCH) Le Tallec, P; Vidrascu, M Bull Liaison Lab Ponts Chaussees, Nllg, May-June 1982, P9-16 Considers the problem of calculating the equilibrium positions of elastic bodies undergoing very big deformations. The equations of equilibrl~m are written in combined form, made discrete by the method of finite elements, and solved rammerically by an augmented Lagrangian algorithm. Several examples of the aPplication of the calculation prograr~ne are subsequently given.
Properties of Rocks and Soils See also: 831085
Geomechanics Abstracts
General 831001 GEOLOGY, GEGMORPHOLOGY AND GEOTECHNICS Henkel, D J Geotechnique, V32, N3, Sept 1982, P175-19~ The Importamce of collaboration between geologists and geotechnlcal englneera is emphasized and the cocoon ~nterest ~L geomor!~Olo~r is suggested as a useful llnk to enable both the geological engineering skills to be mobilized. The role of geccorphology in the ~mderstar~ling of soil movements in the Gulf of Mexico during hurricanes is discussed. Attention is dra~n to problems of tropical weathering a~i char~es in soil chemistry which need further study. Some of the problems associated with grou~water lowering in an area underlain by dolomite are described together with the effects on stability of ~zlnor changes in surface dralr~ge of an inclined rock layer. Auth. 831002 RESPONSE CHAPACT~ERI~IqCS OF CYLINDRICAL PIEZGM~S Brand, E W; Premchitt, J Geotechnique, V32, N3, Sept 1982, P203-216 Finite difference solutiorm are presented for the fund~ental process of pore pressure equalization in a soil-plezometer system for cylindrical piezometers. The response-tlme relationships established for cylindrical piezometers are of the same general form as those for spherical piezometers, the exact shape of a particular relationship being a fumction of the piezometer ~roportions, the soll coml~resslbillty and the flexibility of the piezometer measuring system. The cylindrical equalization chart is constructed, which provides a direct means for the analysis of equalization tests in cylindrical piezometers. Interpretation of laboratory tests on piezometers embedded in clay triaxial specimens shows that equalization tests can provide reliable in situ measurements of soil permeability and good estimations of coefficients of consolidation. 831003 NOTE ON THE C O N D U C T M T Y OF EI~CTROLYTES FOR ANALOG MODELS. TECHNICAL NOTE Brand, E W; Premchltt, J Geotech Test J, V4, N3, Sept 1981, P123-125 Durirg the measurement of piezometer shape factors using a liquid electric analog model (consisting of a tank containing an electrolyte ), it was found that the electrolyte resistance was temperature dependent. A study of temperature effects showed that the conductivity of ~ater varied by only 1. 9 per cent per deg C, compared to almost twice as much for cop~er sulphate solution. It was concluded • that tap water was the more suitable electrolyte to achieve accurate measurements of piezometer shape factors.
831004 ON PHYSICAL MODELLING OF ROCK Cheney, J A Geol~hYs Res Lett, vS, NT, July 1981, P719-720 The problems of satisfying similarity between a physical model and the prototype in rock wherein fissures and cracks play a role in ~ s i c a l behaviour is explored. The need for models of large l~hysical dimensions is explained b~t also reefing of models of the same prototype over a wide range of scales is needed to ascertain the influence of lack of slmilitu~e of particular parameters between prototype and model. A large capacity centrifuge would be useful in that respect. Auth. 831005 SIMPLE AND EFFICIENT N~THOD F ~ INI~ODUCING FAULTS INTO FINITE ELEMENT COMPUTATIONS Meloah, H J; Raefeky, A Bull Selsmol Soc Am, V71, N~, Oct 1961, P1391-1400 This paper outlines a new method, the 'split node technique' for introducing fault displacements into finite element numerical computations. The value of the displacement at a single node point shared between two elements depends upon which element it is referred to, thus introducing a displacement discontinudty between the two elements. We shc~ that the modification i~duced by this splitting can be contained in the load vector, so that the stiffness matrix is not altered. The ra~mber of degrees of freedom is not increased by splitting. This method can be implemented entirely on the local element level, ar~ we show rigorously that no net forces or moments are induced on the finite element grid when isoparametric elements are used. This method is thus of great utility in many geological and engineering applications. Auth. 831006 COMBINED METHOD FOR THE CALCULATION OF ELASTIC SOLIDS UND~R HIGH DEFORMATION (IN FRENCH) Le Tallec, P; Vidrascu, M Bull Liaison Lab Ponts Chaussees, Nllg, May-June 1982, P9-16 Considers the problem of calculating the equilibrium positions of elastic bodies undergoing very big deformations. The equations of equilibrl~m are written in combined form, made discrete by the method of finite elements, and solved rammerically by an augmented Lagrangian algorithm. Several examples of the aPplication of the calculation prograr~ne are subsequently given.
Properties of Rocks and Soils See also: 831085