Showing papers in "Geotechnique in 1973"
TL;DR: In this paper, a simple but accurate method of stability analysis of embankments and slopes is developed to determine the critical earthquake acceleration that is required to bring a mass of soil, bounded by a slip line of any shape and the free surface, to a state of limiting equilibrium.
Abstract: A simple but accurate method of stability analysis of embankments and slopes is developed to determine the critical earthquake acceleration that is required to bring a mass of soil, bounded by a slip line of any shape and the free surface, to a state of limiting equilibrium. At the same time, the usual factor of safety can be determined. It is based on the principle of limiting equilibrium and the method of slices. Effective stress strength parameters are used. A distribution of internal body forces is found based on a simple assumption. This depends on the geometry of the dam and the sliding surface as well as on the strength of the material. Though a computer is used for the calculations presented in the Paper, it is not essential. As in any solution, the physical acceptability of the complete solution must be checked before accepting the result. It is suggested to use the critical acceleration as a measure of the factors of safety. On a mis au point une methode simple mais precise pour l'analyse de la ...
531 citations
TL;DR: In this article, the importance of predictions to the practice of civil engineering is emphasized and illustrates the need for devices and techniques to determine, in situ and continuously with depth, fundamental subsoil properties, such as stress, strength and stress-strain modulus.
Abstract: This Lecture emphasizes and illustrates the importance of predictions to the practice of civil engineering. Predictions are examined and classified, and comparisons are made between predicted performance and measured performance for eight constructed facilities. Although there are many techniques for predicting internal stresses, deformations and stability for a geotechnical facility, the application of these techniques haslimitations. The major limitations are the difficulty of determining fully and accurately the field situation and the mechanisms which will occur, and the selection of soil parameters to use with prediction methods. The greatest need appears to be for devices and techniques to determine, in situ and continuously with depth, fundamental subsoil properties, such as stress, strength and stress-strain modulus. Cette communication insiste sur l'importance des previsions dans la pratique du Genie Civil, et donne des exemples de cette importance. On examine et on classifie divers types de prev...
292 citations
TL;DR: In this article, the authors investigated the volume change behavior of saturated kaolinite and montmorillonitic clays in the light of the modified effective stress concept which takes into considera- tion the interparticle electrical attractive and repul- sive forces.
Abstract: Synopsis This investigation deals with the mechanisms con- trolling the one-dimensional volume change beha- viour of saturated kaolinite and montmorillonitic clays. An attempt has been made to explain the behaviour of the clays in the light of the modified effective stress concept which takes into considera- tion the interparticle electrical attractive and repul- sive forces. Eight organic pore fluids of different dielectric properties and water have been used to vary the interparticle forces in the one-dimensional consolidation tests. In order to further confirm the nature of the mechanisms, tests have also been con- ducted in which the existing pore fluid was replaced by another of different dielectric properties, to change the force system at interparticle level. The experimental results clearly indicate that the volume change behaviour of these clays is controlled basi- cally by two mechanisms which are governed by the modified effective stress concept. In mechanism 1, the volume change is controlled ...
235 citations
TL;DR: In this paper, the bearing capacity of rigid strip footings is shown to depend markedly on the breadth, and to a small extent on the roughness of the underside of the footing, and the analysis can also be applied to the stability of embankments on soft soils.
Abstract: By means of the theory of plasticity, solutions are obtained to the problem of bearing capacity of clay (φ=0) which is inhomogeneous in the vertical direction only. It is shown that the rate of increase of cohesion with depth plays the same role as density plays in the bearing capacity of homogeneous cohesive-frictional soils. When considered in relation to reclamation of swampy areas by sand filling, the results suggest that only very flat slopes of the edge of the filling are possible without the creation of a mud wave. The bearing capacity of rigid strip footings is shown to depend markedly on the breadth, and to a small extent on the roughness of the underside of the footing. The analysis can also be applied to the stability of embankments on soft soils. Finally, comparison between the plasticity and slip circle solutions reveals very serious overestimates in the latter when inhomogeneity dominates. Au moyen de la theorie de la plasticite on trouve des solutions au probleme de portance de l'argile (φ=...
199 citations
TL;DR: Owing to the development of oil and gas fields in the North Sea, the Norwegian Geotechnical Institute has in recent years become involved in extensive investigations of the sea bed.
Abstract: Owing to the development of oil and gas fields in the North Sea, the Norwegian Geotechnical Institute has in recent years become involved in extensive investigations of the sea bed. Work has been c...
167 citations
TL;DR: In this paper, a method of assessing the stability of EMBANKMENTS is described, which is applicable to any shape of SLIP SURFACE with or without a TENSION CRACK.
Abstract: A METHOD OF ANALYSING THE STABILITY OF EMBANKMENTS IS DESCRIBED WHICH ACCOUNTS FOR THE INTER-SLICE FORCES AND SATISFIES FORCE AND MOMENT EQUILIBRIUM CONDITIONS. THE METHOD IS APPLICABLE TO ANY SHAPE OF SLIP SURFACE WITH OR WITHOUT A TENSION CRACK. EXPRESSIONS ARE GIVEN FROM WHICH THE POSITIONS OF THE LINES OF THRUST FOR TOTAL AND EFFECTIVE STRESS CAN BE OBTAINED. SOLUTIONS ARE GIVEN TO TWO SERIES OF PROBLEMS. IN THE FIRST SERIES THERE IS NO TENSION CRACK BUT VARIOUS SHAPES ARE ASSUMED FOR THE SHAPE OF THE SLIP SURFACE AND DIFFERENT ASSUMPTIONS MADE REGARDING THE SLOPES OF THE INTER-SLICE FORCES. HOWEVER, NONE OF THESE SOLUTIONS LEADS TO A SATISFACTORY POSITION FOR THE LINE OF THRUST FOR EFFECTIVE STRESS. IN THE SECOND SERIES A TENSION CRACK WITH WATER PRESSURE ACTING IN IT IS ASSUMED PRESENT. IT IS SHOWN THAT A SATISFACTORY THRUST LINE IS OBTAINED WHEN THE DEPTH OF THE TENSION CRACK IS TAKEN TO BE THE DEPTH OF ZERO ACTIVE EFFECTIVE STRESS AND THE SLOPE OF THE INTER-SLICE FORCES IS CONSTANT, EXCEPT FOR A REDUCTION AT THE UPPER END OF THE SLIP SURFACE. THE INCLUSION OF THE TENSION CRACK WITH WATER PRESSURE ACTING IN IT DOES NOT AFFECT THE VALUE OF THE FACTOR OF SAFETY IN THIS PROBLEM. /TRRL/
146 citations
TL;DR: In this paper, the authors describe three field examples which came from contrasting structural settings; the first example comes from the much folded Upper Carboniferous of North Devon, the second from the less disturbed Carboniferrous of South Wales and the third from the altered Pre-Cambrian of the Scottish Highlands.
Abstract: Toppling failure in the slopes of hard rock masses is a mode of movement that has only been described in the last few years. Much of the work that has appeared in the literature to date deals with the development of this mode in models. This Paper describes three field examples which came from contrasting structural settings. Each involves a different scale of mass movement; the first example comes from the much folded Upper Carboniferous of North Devon, the second from the less disturbed Carboniferous of South Wales and the third from the much altered Pre-Cambrian of the Scottish Highlands. The examples indicate that this mode of failure requires neither unusual geological conditions, nor unusual geological materials in order to develop; in fact the reverse would seem to be true. Les ecoulements au sein des pentes de masses de roche dure representent un type de mouvement qui n'est decrit que depuis quelques annees. Une grande partie du travail publie a ce jour traite du developpement de ce phenomene sur ...
139 citations
TL;DR: In this article, the pore porosity ratio in terms of porosity, compressibility of pore water, soil grains, and soil skeleton was derived from first principles, and the authors discussed the importance of using the excess of total stress over pore pressure in calculations rather than the effective stress relating to volume change.
Abstract: The author describes some earlier work directed at predicting and measuring the pore pressures that are set up by changes in the state of stress of soils, under undrained conditions. He shows how he has derived from first principles an expression of pore porosity ratio in terms of porosity, compressibility of the pore water, compressibility of the soil grains and compressibility of the soil skeleton. It is indicated how the same expression can be derived from Geertsma's equation relating the change in volume of pore space to the changes in total stress and pore pressure. It is stated that the methods of analysis used by Gassman led to conclusions that were consistent with the author's and Geertsma's findings. This is followed by a discussion of the principle of effective stress and, in particular, the importance of using the excess of total stress over pore pressure in the calculations rather than the effective stress relating to volume change. The author then discusses the predicted range of values of pore pressure ratio and concludes with a derivation of the pore pressure parameter as defined by Skempton.
113 citations
TL;DR: The properties of two soil groups widely found in Java and Sumatra are studied in this article, which are known pedologically as latosols and andosols, and are formed under tropical weathering conditions from volcanic parent material.
Abstract: The properties of two soil groups widely found in Java and Sumatra are studied. The two groups, closely related, are known pedologically as latosols and andosols, and are formed under tropical weathering conditions from volcanic parent material. The latosols are reddish in colour and are found at altitudes up to about 1000 m, while the andosols are yellowish brown in colour and are found at greater altitudes. Basic properties, particularly Atterberg limits, specific gravity and compaction characteristics are investigated in the natural state and after air and oven drying. The properties within each group are shown to be similar but are related more closely to mineralogical composition than to pedological classification. Some basic in situ properties, including undrained shear strength, sensitivity and degree of saturation, are also investigated. On etudie les proprietes de deux groupes de sols communement trouves a Java et Sumatra. Les deux groupes extremement semblables, sont designes en pedologie par le...
94 citations
87 citations
TL;DR: In this paper, it is shown that the RESIDUAL FACTOR may be computed using this method, and the results of the finite element analysis may be directly applied to STABILITY ANALYSIS in STRAIN-SOFTENING MATERIALS.
Abstract: COMPUTER PROGRAMS WERE DEVELOPED USING THE FINITE ELEMENT METHOD TO APPROXIMATE A SOLUTION FOR STRESSES AND DISPLACEMENTS IN SLOPES OF STRAIN-SOFTENING MATERIAL. THE TREATMENT OF THE POST-PEAK BEHAVIOR IN THE ANALYSIS IS DISCUSSED. THE RESULTS ACHIEVED APPEAR TO BE CONSISTENT WITH FIELD OBSERVATIONS. IT IS SHOWN THAT THE RESIDUAL FACTOR MAY BE COMPUTED USING THIS METHOD, AND THE RESULTS OF THE FINITE ELEMENT ANALYSIS MAY BE DIRECTLY APPLIED TO STABILITY ANALYSIS IN STRAIN-SOFTENING MATERIALS. /AUTHOR/
TL;DR: In this article, the authors show that failure of slopes cut in overconsolidated clay may be delayed by the rate of equilibration of pore pressure after excavation, which is the principal mechanism controlling delayed failure in the London Clay.
Abstract: Failure of slopes cut in overconsolidated clay may be delayed by the rate of equilibration of pore pressure after excavation. Other mechanisms, such as decrease in drained strength with time, have been suggested as reasons for delayed failure. Previous studies of cutting slopes in the London Clay have suggested that equilibration of pore pressure is relatively rapid and that other mechanisms control eventual failure. Recent observations of pore pressure in a cut slope nine years after excavation suggest that equilibration of pore pressure may be the principal mechanism controlling delayed failure in the London Clay. The studies made of failures in London Clay slopes have played a significant part in the general study of long-term failure of cut slopes in clay, so this conclusion has some general implication. La rupture des talus decoupes dans de l'argile surconsolidee peut etre retarde par la vitesse d'equilibrage de la pression interstitielle apres excavation. D'autres mecanismes tels que la reduction de...
Journal Article•
TL;DR: The authors showed that RESIDUAL SHEAR STRENGTH IS PRIMARILY DEPENDENT ON MINERAL COMPOSITION and system CHEMISTRY and that STRENGTH and PLASTICITY can be correlated.
Abstract: THE AUTHOR DRAWS ATTENTION TO THE FACT THAT DRAINED DIRECT SHEAR TESTS BY NUMEROUS WORKERS ON NATURAL SOILS, PURE MINERALS AND MINERAL MIXTURES HAVE SHOWN THAT RESIDUAL SHEAR STRENGTH IS PRIMARILY DEPENDENT ON MINERAL COMPOSITION AND SYSTEM CHEMISTRY. THESE NUMERALOGICAL FACTORS AFFECT ATTERBERG INDEX PARAMETERS. IT DOES NOT SEEM SURPRISING THAT STRENGTH AND PLASTICITY CAN BE CORRELATED. /TRRL/
TL;DR: In this article, a linear relationship between volumetric strain and porosity is established for porous soils, and the authors show that porosity or dry density is a more reasonable basis for describing and grouping of these soils for engineering purposes.
Abstract: The Paper illustrates how high porosity, a strongly cemented structure and highly hydrated kandite clay minerals control the geotechnical properties of residual sandy to silty clay soils of the Papua New Guinea highlands. These soils are characterized by high field moisture contents, relatively high shear strengths and low sensitivity, and are highly compressible when the applied pressure in an oedometer test exceeds a certain critical pressure. Measured values of critical pressure and compression index are compared with those reported for a wide variety of soils, and a linear relationship between volumetric strain and porosity is established for porous soils. The natural inhomogeneity of residual soils is emphasized. Examination of relationships between geotechnical properties and porosity and moisture content shows that porosity or dry density is a more reasonable basis for description and grouping of these soils for engineering purposes. The behaviour of the soils is interpreted in terms of an idealize...
TL;DR: In this article, the authors show how the solutions may be used to improve the perception of set-lements and stress on a FOOTING RESTing on a clay or sand.
Abstract: A FINITE ELEMENT COMPUTER PROGRAM IS USED TO SOLVE THE SETTLEMENT AND STRESSES INDUCED BY A RIGID CIRCULAR PLATE RESTING ON A NON-HOMOGENEOUS ELASTIC HALF-SPACE. THE SOLUTIONS ARE COMPARED WITH CLOSED FORM SOLUTIONS AND THE COMPUTER SOLUTIONS AGREE WITH THE THEORETICAL SOLUTIONS. THE COMPUTER SOLUTIONS ALLOW AN ENGINEER TO CALCULATE THE SETTLEMENT OF A PLATE FOR ANY COMBINATION OF YOUNG'S MODULUS OF ELASTICITY, SLOPE OF THE CURVE EXPRESSING THE LINEAR INCREASE OF YOUNG'S MODULUS WITH DEPTH Z, POISSION'S RATIO, V, G (THE UNIT LOAD ON THE PLATE) AND D (THE PLATE DIAMETER). THIS PAPER SHOWS HOW THE SOLUTIONS MAY BE USED TO IMPROVE THE PREDICTION OF SETTLEMENTS AND STRESSES BENEATH A FOOTING RESTING ON A CLAY OR SAND. FOR MOST PRACTICAL PROBLEMS, THE SOLUTION FOR A ROUGH PLATE IS THE SAME AS THE SOLUTION FOR A SMOOTH PLATE. /TRRL/
Journal Article•
TL;DR: In this article, a simple but accurate method of stability analysis of embankments and slopes is developed to determine the critical earthquake acceleration that is required to bring a mass of soil, bounded by a slip line of any shape and the free surface, to a state of limiting equilibrium.
Abstract: A simple but accurate method of stability analysis of embankments and slopes is developed to determine the critical earthquake acceleration that is required to bring a mass of soil, bounded by a slip line of any shape and the free surface, to a state of limiting equilibrium. At the same time, the usual factor of safety can be determined. It is based on the principle of limiting equilibrium and the method of slices. Effective stress strength parameters are used. A distribution of internal body forces is found based on a simple assumption. This depends on the geometry of the dam and the sliding surface as well as on the strength of the material. Though a computer is used for the calculations presented in the paper, it is not essential. As in any solution, the physical acceptability of the complete solution must be checked before accepting the result. It is suggested to use the critical acceleration as a measure of the factors of safety. /AUTHOR/
TL;DR: Variations in seismic velocity with depth have been measured in the Middle Chalk at the proposed 300 GeV proton accelerator site at Mundford, Norfolk, where they could be compared with the results obtained from a geological and geotechnical survey as discussed by the authors.
Abstract: Variations in seismic velocity with depth have been measured in the Middle Chalk at the proposed 300 GeV proton accelerator site at Mundford, Norfolk, where they could be compared with the results obtained from a geological and geotechnical survey. It is shown that the seismic velocity increases with depth in clearly defined steps, and that these steps broadly correspond with some of the grades in the engineering classification adopted by the geotechnical survey. Correlation has also been obtained between the seismic results and the thickness of the overlying sandy drift, and with tectonic structures in the chalk. On a mesure les variations de la vitesse de propagation des ondes sismiques en fonction de la profondeur dans le Calcaire Moyen du site qui a ete propose a Mundford (Norfolk), pour l'accelerateur de protons de 300 GeV ou on pouvait les comparer aux resultats obtenus a partir des etudes geotechniques et geologiques. On montre que la vitesse de propagation augmente en fonction de la profondeur sui...
TL;DR: In this paper, the authors examined Coulomb's analysis of the earth pressure on a vertical retaining wall in the light of modern theory of plasticity and gave a derivation of formulae for pressures on both smooth and rough retaining walls.
Abstract: The author examines Coulomb's analysis of the earth pressure on a vertical retaining wall in the light of modern theory of plasticity. His work was prompted by Heyman's comment that Coulomb's expression cannot be applied when the wall is rough and that the thrust estimates are therefore not strict bounds. He first discusses upper and lower bound theorems and points out that although they hinge critically on the assumption of a normal or associated flow rule, the normal flow rule can still be used to provide upper bounds of the failure loads even when the real soil behaves incompressibly. An account is given of the derivation of formulae for pressures on both smooth and rough retaining walls. The fact that his kinematic argument appears to differ from Heyman's yet yields the same formula is briefly disscussed. An appendix gives a proof of the author's statement that "the internal rate of working of the stresses in any virtual mechanism, compatible with the yield condition, cannot be less than the sum of the rate of the rate of working of the actual body forces and surface tractions with the virtual velocity field. /TRRL/
TL;DR: In this article, the results of the measurements of horizontal and vertical movement in instrumented vertical boreholes drilled prior to bentonite-supported excavation of a trench in London clay were described.
Abstract: The note describes the results of the measurements of horizontal and vertical movement in instrumented vertical boreholes drilled prior to bentonite-supported excavation of a trench in London clay. The analytical approach involves equating the supporting forces acting on the excavation side wall with disturbed forces acting in an assumed failure wedge behind the sidewall. As it is difficult to postulate the pressure distribution behind a slurry supported sidewall, direct observations are made and reported. It is observed that the deformation is mainly horizontal, the maximum occurring uniformly at a depth of 5-6 meters, and that the ground is not affected 6.1 meters from the side wall, the excavation trench being 6.1 meters long, 0.8 meters wide, and 15 meters deep. /TRRL/
TL;DR: In this article, the authors explored the application of stereo-photogrammetry to the measurement of planar displacement fields using anaglyph slides and showed that the results can be obtained to within 5 micrometers using a photogrammetric technique.
Abstract: The note explores the application of stereo-photogrammetry to the measurement of planar displacement fields. A research program at Southampton University has extended the basic theory of the method to include determination of strain fields and velocity holographs from the displacements, detailed measurement of complex patterns of water surface velocities and the use of anaglyph slides. The note examines the possibility of detecting displacements of individual sand particles in a plane to at least 5 micrometer sensitivity. The angular rotation of individual sand grains during displacement is studied and the detailed information obtained by stereo-photogrammetry is compared with that provided by an embedded grid of discrete markers in the soil model. The investigation establishes that planar displacement of individual sand grains in a deforming model can be measured to within 5 micrometers using a photogrammetric technique. /TRRL/
TL;DR: In this article, a series of shear tests were performed with intact and jointed overconsolidated clay samples and along different types of structural discontinuities of jointed clay.
Abstract: Drained shear tests were performed with shear boxes on intact samples and along different types of structural discontinuities of jointed overconsolidated clay. In the intact clay, a slight anisotropy of strength and brittleness was observed. Along joints, the friction angle was found to be the same as that for the intact clay, and there was a small cohesion which was probably due to the plumose texture of the joint surfaces. The strength along fault planes coincides with the residual strength of intact and jointed clay. These results confirm the hypothesis previously advanced (ESU and Calabresi, 1969) in the analysis of short-term slides that occurred in this clay during the excavation of high cuts. On presente une serie d'essais de cisaillement draine d'une argile surconsolidee. On a mesure la resistance au cisaillement le long des joints naturels et on l'a comparee avec celle du materiau non fissure. Une legere anisotropie de la resistance et de la fragilite a ete remarquee dans l'argile. Le long des jo...
TL;DR: In this article, a closed pressure system is adapted so that any tendency for water to be transported through the soil specimen is opposed by a rise in pressure at the cathode, which is measured by means of a balancing air pressure in a chamber adjoining a flexible diaphragm.
Abstract: The note describes the electro-osmotic pressure apparatus used to determine the coefficient of electro-osmotic permeability of soil. A closed pressure system is adapted so that any tendency for water to be transported through the soil specimen is opposed by a rise in pressure at the cathode. This pressure is measured by means of a balancing air pressure in a chamber adjoining a flexible diaphragm. The initial tangent modulus of the pressure time curve is determined and from the values of applied potential gradient and the calibration constant of the equipment the coefficient of electro-osmotic permeability is worked out the method can be used for routine determination of the electro-osmotic permeability. /TRRL/
TL;DR: In this paper, a new type of falling head permeameter was developed to overcome the shortcomings of the constant head and usual falling-head permeameters when measuring the permeability of a homogeneous clay.
Abstract: The author describes a new type of falling head permeameter which he has developed to overcome the shortcomings of the constant head and usual falling head permeameter when measuring the permeability of a homogeneous clay. The basic principle is the replacement of the capillary tube in the usual type by a pressure transducer. The method is described in detail. A modification of the usual falling head permeameter formula was found to be satisfactory because of the linear relationship between volumetric deformation and pressure for the transducer. Details are given of tests, namely the measurement of the permeability of a montmorillonite traxial sample and of a rubber membrane. In discussing the method, the author points out that the equipment is already available in most laboratories. He found that great care must be taken to saturate fully the sample under test. His main problems were in the various connections and valves and he describes the methods used to check leakage and to ensure that it does not occur at points where it could not be checked. He concludes that the device is quick and easy to use and that although it was mounted on a triaxial cell for his work it could also be used with an oedometer or a permeameter. /TRRL/
Journal Article•
TL;DR: In this paper, the authors discuss the importance of predicting internal stresses, deformation, and stability of GEOTECHNICAL FACILITIES. But, the application of these technologies has limitations and the major limitation is the difficulty of determining fully and accurately the FIELD SITUATION and the MECHANISMS WHICH will OCCUR.
Abstract: THIS LECTURE EMPHASIZES AND ILLUSTRATES THE IMPORTANCE OF PREDICTIONS TO THE PRACTICE OF CIVIL ENGINEERING. PREDICTIONS ARE EXAMINED AND CLASSIFIED, AND COMPARISONS ARE MADE BETWEEN PREDICTED PERFORMANCE AND MEASURED PERFORMANCE FOR EIGHT CONSTRUCTED FACILITIES. ALTHOUGH THERE ARE MANY TECHNIQUES FOR PREDICTING INTERNAL STRESSES, DEFORMATIONS AND STABILITY FOR A GEOTECHNICAL FACILITY, THE APPLICATION OF THESE TECHNIQUES HAS LIMITATIONS. THE MAJOR LIMITATIONS ARE THE DIFFICULTY OF DETERMINING FULLY AND ACCURATELY THE FIELD SITUATION AND THE MECHANISMS WHICH WILL OCCUR, AND THE SELECTION OF SOIL PARAMETERS TO USE WITH PREDICTION METHODS. THE GREATEST NEED APPEARS TO BE FOR DEVICES AND TECHNIQUES TO DETERMINE, IN SITU AND CONTINUOUSLY WITH DEPTH, FUNDAMENTAL SUBSOIL PROPERTIES, SUCH AS STRESS, STRENGTH AND STRESS-STRAIN MODULUS. (A)
TL;DR: In this paper, the authors present a theory of Earth and slow mud flows and compare the theory with OBSERVED ONES. But they do not discuss the causes of these two types of flows.
Abstract: THE AIM OF THIS PAPER IS TO PRESENT A THEORY OF EARTH AND SLOW MUD FLOWS AND TO COMPARE CALCULATED PROFILES WITH OBSERVED ONES. THE MATERIAL OF AN EARTH FLOW OR OF A SLOW MUD FLOW IS CHARACTERIZED BY THE COHESION C. THE SHEARING STRESS AT THE SLIP PLANE IS ASSUMED TO BE THE SUM OF THE COHESION AT SLIP PLANE AND AN AMOUNT OF FRICTION CHARACTERIZED BY AN ANGLE OF FRICTION AT SLIP PLANE WHICH IS IN ACCORDANCE WITH THE LAWS OF SOIL MECHANICS. IF THE EXISTENCE OF AN ACTIVE OR A PASSIVE RANKINE STATE OF STRESS IS ASSUMED, IT IS POSSIBLE TO COMPUTE THEORETICAL PROFILES OF EARTH FLOW OR MUD FLOW TONGUES. A DISCUSSION OF THE CAUSES OF MOTION SHOWS THAT THE EXISTENCE OF AN ACTIVE RANKINE STATE IS MOST PROBABLE IN NATURE. A COMPARISON OF THEORETICAL AND OBSERVED PROFILES OF EARTH FLOW TONGUES FOR TWO EXAMPLES YIELDS AGREEMENT. THE COHESION AT THE SLIP PLANE IS 50-100% OF THE COHESION OF THE FLOWING MATERIAL, WHICH IS SUPRISINGLY HIGH. /TRRL/
TL;DR: In this article, a case record of the slope failure that initiated the retrogressive quick-clay landslide at Ullensaker, Norway is presented, where initial topography is known, the size of the initial slope failure was witnessed, the approximate location of the slip surface was determined by borings and the water pressures are approximately known from measurements in an adjacent slope.
Abstract: A case record is presented of the slope failure that initiated the retrogressive quick-clay landslide at Ullensaker, Norway. Information concerning the landslide is reasonably complete: initial topography is known, the size of the initial slope failure was witnessed, the approximate location of the slip surface was determined by borings and the water pressures are approximately known from measurements in an adjacent slope. A comprehensive series of drained triaxial compression tests was conducted on undisturbed samples. Effective stress stability calculations of the slope yielded an apparent safety factor of unity. On presente l'histoire d'un cas de rupture de pente qui a declenche un glissement de terrain retrograde dans une angile fluide a Ullensaker, Norvege. L'information sur ce glissement est raisonnablement complete: on connait la topographie initiale, les dimensions du glissement initial ont ete observees, la position approximative de la surface de glissement a ete determinee par forage, et les pre...