Showing papers on "Discontinuity (geotechnical engineering) published in 1968"
TL;DR: In this article, a linkage type element is developed for adding rock joint stiffness to the structural stiffness matrix describing the behavior of a system of rock blocks and joints and a new classification of joints is introduced, based on the application of the joint element to finite element analysis of structures in jointed rock.
Abstract: The representation of discontinuities in analysis of blocky rock is discussed. A linkage type element is developed for addition of rock joint stiffness to the structural stiffness matrix describing the behavior of a system of rock blocks and joints. Several basic problems of jointed rock are studied. These examples demonstrate the marked influence joints may have on the stress distribution, displacements, and failure pattern of an underground opening or other structures in jointed rock. A new classification of joints is introduced, based on the application of the joint element to finite element analysis of structures in jointed rock. Normal stiffness, tangential stiffness, and shear strength are used as parameters in the classification system. The methods discussed in this paper allow a jointed rock mass to be treated as a system of blocks and links. Just as analysis of a reinforced concrete building requires detailed knowledge of the behavior of concrete alone and steel alone, the joint stiffness approach calls for and uses detailed description of the behavior of rock blocks and rock joints independently.
1,186 citations
TL;DR: In this article, it was shown that if there is a discontinuity in depth along a straight line separating two regions each of uniform depth, then wave motions may exist which are propagated along the discontinuity and whose amplitude falls off exponentially to either side.
Abstract: It is shown that, according to the linearized theory of long waves in a rotating, unbounded sea, if there is a discontinuity in depth along a straight line separating two regions each of uniform depth, then wave motions may exist which are propagated along the discontinuity and whose amplitude falls off exponentially to either side. Thus the discontinuity acts as a kind of wave-guide.The period of the waves is always greater than the inertial period. The wave period also exceeds the period of Kelvin waves in the deeper medium. As the ratio of the depth tends to infinity, the wave period tends to the inertial period or to the Kelvin wave period, whichever is the greater. On the other hand as the wavelength decreases (within the limits of shallow-water theory) so the waves tend to the non-divergent planetary waves found recently by Rhines.In an infinite ocean of uniform depth free waves with period greater than a pendulum-day cannot normally be propagated without attenuation (if the Coriolis parameter is constant). But non-uniformities of depth provide a means whereby such energy may be channelled over great distances with little attenuation.It is suggested that a gradually diminishing discontinuity will act as a chromatograph, each position along the discontinuity being marked by waves of a particular period.
88 citations
TL;DR: In this article, the authors extended the mathematical model of the vertical strike-slip fault to include a net displacement that varies over the face of the fault, which is chosen so as to remove the stress singularity that occurs at the edge of fault plane.
56 citations
TL;DR: In this paper, the general character of the linear elastic solution near the periphery of the crack is determined such that local stresses and displacements can be expressed independently of uncertainties of both the crack geometry and magnitude of the applied load.
39 citations
28 citations
01 Jan 1968
22 citations
TL;DR: In this paper, it was shown that Danckwerts' boundary conditions at the entrance and exit to throughflow equipment with significant axial diffusivity only in the equipment proper are a natural consequence of the second law of thermodynamics as applied to the irreversible processes of simultaneous heat and mass transfer in one-dimensional systems with internal surfaces of discontinuity.
22 citations
Patent•
26 Jul 1968TL;DR: In this paper, a rubberized cord belt construction for use in either a radial or bias ply tire is described, where mutually parallel alignments of discontinuous cord lengths replace the conventional parallel continuous cords and the elastomer of the belt contains uniformly dispersed, oriented, filaments.
Abstract: Disclosed is a rubberized cord belt construction, for use in either a radial or bias ply tire, where mutually parallel alignments of discontinuous cord lengths replace the conventional parallel continuous cords and the elastomer of the belt contains uniformly dispersed, oriented, filaments. The cord alignments are disposed at a small angle relative to the crown of the tire. Because of the discontinuity of the cords, the belt may be expanded. Thus, tires employing these low-angle belts may be manufactured by presently existing tire-shaping equipment.
15 citations
TL;DR: The anomalous scattering persists in the Os-Ir alloys, where magnetic measurements indicate that no magnetic moment resides on the Fe impurities as mentioned in this paper, and the resistivity due to the Fe has a strong anomalous temperature dependence which scales linearly with Fe concentration and changes gradually with host composition.
Abstract: The resistivity has been measured as a function of temperature for Fe dissolved in Ir, and in some Os-Ir and Ir-Pt alloys The resistivity due to the Fe has a strong anomalous temperature dependence which scales linearly with Fe concentration and changes gradually with host composition No discontinuity in the behavior of the resistivity was found at Ir-Fe to correspond to the discontinuity in susceptibility observed by Geballe et al The anomalous scattering persists in the Os-Ir alloys, where magnetic measurements indicate that no magnetic moment resides on the Fe impurities
Patent•
18 Oct 1968
TL;DR: In this article, a square socket-type head for screw fasteners, and punch for forming same is described, in which the socket has four equal sides each of which has an upper slightly inwardly inclined flat portion which merges without discontinuity at its lower end with a lower concave bottom portion.
Abstract: Square socket-type head for screw fasteners, and punch for forming same, in which the socket has four equal sides each of which has an upper slightly inwardly inclined flat portion which merges without discontinuity at its lower end with a lower concave bottom portion.
01 Jan 1968
TL;DR: The surface as a physical discontinuity affects many of the mechanical properties of metals as mentioned in this paper, and the basic consequences of the existence of the surface, its influence on dislocation dynamics, and finally the resulting effects on macroscopic plastic behavior are discussed.
Abstract: The surface as a physical discontinuity affects many of the mechanical properties of metals. The basic consequences of the existence of the surface, its influence on dislocation dynamics, and finally the resulting effects on macroscopic plastic behavior are discussed.
01 Jun 1968
TL;DR: In this paper, a two-dimensional time dependent numerical model of the atmospheric boundary layer is formulated and used to investigate various characteristics of air motion when a change occurs in roughness and/or temperature characteristics of the underlying surface.
Abstract: : A two-dimensional time dependent numerical model of the atmospheric boundary layer is formulated and used to investigate various characteristics of air motion when a change occurs in roughness and/or temperature characteristics of the underlying surface. The integrations have been carried out for steady-state situations also. The model incorporates the effects of penetrative convection, diabatic influence associated with small-scale eddy diffusion, and pressure effects induced by horizontal nonuniformity of terrain in temperature and roughness. The results show that warm surfaces do not necessarily increase the height of internal boundary layers in the vicinity of surface discontinuity. The effects of discontinuity are quite appreciable at large fetches downwind from the discontinuity. (Author)
TL;DR: In this paper, the authors used two-dimensional, layered structures constructed by lead-aluminum laminations as the models and measured head-wave amplitude and phase responses in a frequency range of 25 kHz to 200 kHz.
Abstract: Ultrasonic, seismic-model experiments have been performed to re-examine the nature of head waves from a transition layer. Two-dimensional, layered structures, some with a transition zone and some with a sharp discontinuity, constructed by lead-aluminum laminations have served as the models. Amplitude and phase responses have been measured in a frequency range of 25 kHz to 200 kHz. At low frequencies, where the wavelength is much longer than the thickness of the transition zone, little difference is observed between head waves from a transition zone and those from a sharp discontinuity. At a certain frequency range where the wavelength is close to the thickness of the transition zone, the measured head-wave amplitude from a transition zone becomes a few times larger than that from a sharp discontinuity. This is characteristic of head waves from a poorly defined boundary and may be used to estimate the thickness of a general transition layer. A sharp, high-frequency cutoff is again observed, but the cutoff frequency is not consistent with previous studies.
01 Oct 1968
TL;DR: A SHEAR test is described in this paper, which is used to verify the strength of different types of brittle structures in a set of different shapes of rock, such as bedding planes, cleft or fracture planes.
Abstract: THE SHEAR STRENGTH PROPERTIES ALONG DISCONTINUITIES (BEDDING PLANES, CLEFT OR FISSURE PLANES) IN ROCK ARE OF PRIMARY INTEREST FOR THE SOLUTION OF PRACTICAL STABILITY PROBLEMS IN THE ROCK MECHANICS FIELD. A SHEAR TEST IS DESCRIBED WHICH MAINLY DETERMINES THE FRICTION ANGLE IN SUCH DISCONTINUITIES. THE PAPER GIVES RESULTS OF TESTS ON DIFFERENT TYPES OF ROCK. /RRL/
TL;DR: In this article, it was shown that the velocity discontinuity between a plasmavacuum interface is always unstable to small perturbations when the effect of gravity is taken into account.
Abstract: It is shown that the velocity discontinuity between a plasmavacuum interface is always unstable to small perturbations when the effect of gravity is taken into account.
01 Oct 1968
TL;DR: In this paper, the authors discuss the relation of a DAM to its foundation and its role in the development of the SHEAR STRENGTH CHARACTERISTICS of the ROCK MASS.
Abstract: THE RELATION OF A DAM TO ITS FOUNDATION ROCK MASS IS DISCUSSED, EMPHASIZING THE SHEAR STRENGTH CHARACTERISTICS OF THE ROCK MASS. THE IMPORTANCE OF DISCONTINUITIES WHICH USUALLY GOVERN THE STABILITY IS NOTED AND SOME METHODS OF OBTAINING THE SHEAR STRENGTH CHARACTERISTICS ARE GIVEN. THE INCLINED-SINGLE-JACK-MOUNTING IS REFERRED TO FOR THE IN SITU TESTS. SOME CONSIDERATIONS OF THE COMMON TYPE OF IN SITU SHEAR TESTS ARE PRESENTED, PARTICULARLY THE COMPLEXITY OF THE PHENOMENON OF RUPTURE IN ROCK MASSES AND THE VARIOUS CRITERIA TO DEFINE THE MOMENT OF FAILURE, ALONG WITH THE REASONS FOR CONSIDERING MOHR'S THEORY OF RUPTURE AS APPLICABLE TO IN SITU TESTS. PRACTICAL CONSIDERATIONS OF THE AREA TO BE TESTED ARE ALSO GIVEN. THE PLANS OF THE TESTS AND THE PRINCIPAL RESULTS OBTAINED FROM THE SHEAR TESTS CARRIED OUT FOR THE STUDIES OF THE ROCK FOUNDATIONS OF GRAN SUARNA, LAS PORTAS, AND JANOVAS DAMS ARE PRESENTED. THESE RESULTS SHOW THAT THE INTERRELATION OF THE TESTED BLOCK AND THE LOWER ROCK HAS A GREAT INFLUENCE ON THE MEASURED DISPLACEMENTS. IN THE CASE OF DISCONTINUITIES WITH LITTLE OR NO INTERRELATION, AS WITH A CLAY-FILLED DISCONTINUITY, IT SEEMS THAT THERE IS A DANGER OF FAILURE WITHOUT ANY PREVIOUS WARNING FROM THE DEFORMATIONS OF THE SUPERSTRUCTURE. THE IMPORTANCE OF TREATMENTS WHICH PROVIDE AN INTERRELATION OF THE TWO SURFACES IS CONSEQUENTLY EMPHASIZED. /RRL/
TL;DR: In this paper, the general solution to the dislocation problem is considered for anisotropic media which have a plane of elastic symmetry for the plane strain and anti-plane strain deformation cases.
Abstract: The general solution to the dislocation problem is considered for anisotropic media which have a plane of elastic symmetry for the plane strain and anti-plane strain deformation cases. The displacement discontinuity function is assumed to satisfy a Holder condition for all points along the dislocation cut. It is shown that the general dislocation problem can be identified with the Hilbert problem, and can effectively be reduced to the customary boundary value problems of plane or antiplane elasticity. The general properties of the solution functions are discussed. The case of a set of Volterra dislocations is given as an illustrative example.
TL;DR: In this article, a theory of crack opening displacement using the model of dislocations, developed by Bilby, Cottrell, Swinden, has recently appeared before the footlight.
Abstract: There have been many theoretical investigations for brittle fracture initiation. Among them, a theory of crack opening displacement using the model of dislocations, developed by Bilby, Cottrell, Swinden, has recently appeared before the footlight. The theory would be especially to be available even for the phenomena of the initiation of the brittle fracture initiation at considerably high stress level such as near the general yield condition.The authors tried to extend the theory of the crack opening displacement to the problems for arbitrarily distributed stress field and to apply to analysis for “Longitudinally Welded I-Type Test” which has structural discontinuities and ununiform welding residual stresses. The calculation results are in good agreement with the experimental ones.In connection with calculation, further, the authors examined the brittle fracture initiation in the steel plate with deep edge notches, of which tip is at the boundary of plate thickness discontinuity, and proposed by some theoretical consideration the effective crack length for brittle fracture initiation into the different thickness plate.
TL;DR: In this paper, the authors show that axisymmetric boundary layers with surface slope discontinuities or other nonuniformities exhibit a number of features which are absent in the planar case, such as the dependence of the rate decay of disturbance caused by a slope discontinuity on the transverse curvature of the discontinuity.
Abstract: T phenomena encountered in inviscid flows past axisymmetric bodies with surface slope discontinuities or other nonuniformities exhibit a number of features which are absent in the planar case. A good example is the dependence of the rate decay of a disturbance caused by a slope discontinuity on the transverse curvature of the discontinuity. These features, interpreted qualitatively, indicate some important differences to be expected in the development of axisymmetric boundary layers.
TL;DR: Plasma oscillation modes perpendicular to magnetic field used to study energy conversion by wave coupling across density discontinuity were used in this article, where the authors showed that they can be used to measure energy conversion.
Abstract: Plasma oscillation modes perpendicular to magnetic field used to study energy conversion by wave coupling across density discontinuity