Slide Plane Research Articles

A refreshing 3D view of an ancient sediment collapse and slope failure

The combined analysis of high‐resolution 2D seismics and an industrial 3D seismic data volume from the western Porcupine Basin, offshore SW Ireland, revealed an unusual picture of a buried sediment collapse and slope failure. A proportionally thin (≤ 85 m) but vast (> 750 km2) slab of consolidated sediments started to slide downslope, in the meantime breaking into hundreds of vertically undisturbed blocks, up to 500 m in diameter. The most probably overpressured underlying horizon seems to have liquefied and acted as a slide plane until the excess pore pressure had dissipated. Then – still very early in the slide development – the process stopped, freezing the failure at its initial stage.

719 第一原理計算による Ti_3Al の逆位相境界の特性評価

Ti_3Al is expected as a superior structural material. It shows fine mechanical properties, but it has a problem to lack the ductility at room temperature. The promising solution for this problem is introduction of APD. The APD growth is related to its APB energy. In this paper, we make models of perfect crystal Ti_3Al and crystal with APB which is formed by relative shift of crystal structure along the slide plane and calculate electronic structures of them. It appears that the covalent d-type bonds between titanium atoms exist near APB.

Multiple sector collapses at stromboli volcano, Italy: how they work

This paper demonstrates that four large sector collapses have affected the NW flank of the Stromboli volcano in the past 13 ka, alternating with growth phases, in order to contribute to the evaluation of the critical conditions which trigger lateral collapses, a reconstruction of the geometry of each collapse of the volcano edifice in the four stages that preceded the relative collapse events is also presented, and a computation of the landslide volume. This reconstruction is based on new field data plotted in three dimensions. Prior to the initial 13-ka collapse, the volcano was 1125±100 m high above sea level. The collapse had a volume of 2.23±0.87 km3, whereas the pre-collapse volcano volume was 218.8±7.7 km3. The next edifice that failed was 900±70 m high a.s.l. The collapse volume was 1±0.54 km3, with a precollapse volcano volume of 201.4±5.4 km3. The edifice then grew to 1000±60 m a.s.l. The third collapse had a volume of 1.08±0.39 km3 and occurred within a volcano with a volume of 209.1±4.6 km3. This was followed by a new growth phase followed by the last collapse with a volume of 0.73±0.22 km3. The volcano volume was about the same as the present one. The present active crater zone is at 780 m a.s.l. in the first three collapses, sliding surfaces cut the main magma conduit. In the last collapse, the upper scarp coincided with the conduit location. Dyking along a main NE-trending weakness zone across the volcano summit exerted a lateral force for collapse inception. The decrease of the landslide volumes with the age, and the concentric scarps of the four collapses, suggest that the younger sliding planes tended to become more superficial and to decrease the areal extent. This is interpreted as due to: (a) successively weaker eruptive products from dominantly lavas to dominantly pyroclastics; and (b) the feedback effects between collapses and dykes that injected along the lateral segments of the first collapse slide plane.

Observations and simulations of the formation of the faceted snow crystals in the weak-layer of the 1998 Niseko Haru no Taki avalanche

On January 28, 1998, an avalanche accident occurred near the Japanese ski resort Niseko Alpen in Hokkaido. The following morning, a snow-pit was dug through the fracture line and the snow cover analysed. There was a weak layer of faceted crystals at a depth of 1 m and it was this weak layer that became the slide plane. Meteorological and snow-pit data from a nearby (1 km) site are used with the Crocus model to explain the formation of the faceted crystals as follows. A period of slow surface warming followed by rapid cooling created a large temperature gradient in the layer near the surface of the snow cover which formed a thin layer of faceted crystals near the surface. The large gradient remained as the layer became buried and the faceted crystals survived in the snow cover for 9 days until increasing load from snow accumulation led to failure and the avalanche occurred.

Nonlinear Coupled Seismic Sliding Analysis of Earth Structures

Earthquake-induced sliding displacements of earth structures are generally evaluated using simplified sliding block analyses that do not accurately model the seismic response of the sliding mass nor the seismic forces along the slide plane. The decoupled approximation introduced to capture each of these effects separately is generally believed to be conservative. However, recent studies using linear viscoelastic sliding mass models have revealed instances where the decoupled approximation is unconservative. In this paper, a coupled analytical model that captures simultaneously the fully nonlinear response of the sliding mass (necessary for intense motions) and the nonlinear stick-slip sliding response along the slide plane is presented. The proposed sliding model is validated against shaking table experiments of deformable soil columns sliding down an inclined plane. The effect of sliding on the response of earth structures is evaluated, and comparisons are made between sliding displacements calculated using coupled and decoupled analytical procedures with linear and nonlinear material properties. Nonlinearity resulting from stick-slip episodes is often the dominant source of nonlinearity in this problem. The decoupled approximation was unconservative primarily for intense ground motions for systems with low values of ky, larger values of ky/kmax, and high period ratios (Ts/Tm). Results indicate that a decoupled analysis is adequate for earth structures that are not expected to experience intense, near-fault motions. However, for projects undergoing intense, near-fault ground motions, a fully nonlinear, coupled stick-slip analysis is recommended.

Analysis of vertical pressure on buried pipeline with case study

This paper introduces a formula for the vertical pressure on a buried pipeline by using a modification of the basic assumptions of Marston’s theory. The fill’s cohesion is considered. The included angle between the slide surface above the pipeline and the horizontal surface is assumed to be equal to the fill’s angle of friction. The friction is calculated by multiplying the active earth pressure on the outer column and the coefficient of the friction on the slide planes It was found that the fill’s cohesion had important influence on the vertical pressure, whose vertical pressureC c decreases with increase of the fill depth, a relationship according with that observed in practice. At the end of the paper, the formula is employed to analyze a practical case.

Numerical Models of Translational Landslide Rupture Surface Growth

We analyze the initiation and enlargement of the rupture surface of translational landslides as a fracture phenomenon using a two-dimensional boundary-element method. Both processes are governed largely by the stress field and the pre-existing planes of weakness in a slope. Near the ground surface, the most compressive stress becomes either parallel or perpendicular to the slope, depending on the topography and regional stresses. The shear stress available to drive slope-parallel sliding in a uniform slope thus is small, and therefore pre-existing weaknesses are required in many cases for sliding. Stresses in a uniform slope favor the initiation of sliding near the slope base. Sliding can progress upslope from there in retrogressive fashion. Most slopes are not uniform and notches in a slope will concentrate stresses and generally promote sliding there. As the region of sliding at depth enlarges, the stress concentration near the edge of the area of slip will tend to rise. Stress concentrations can become sufficient to open fractures above and below a basal slide plane, in keeping with observations. If one tip of a slide plane intersects the ground surface, then stresses near the other tip can increase markedly, as can slip. Our analyses show that slope-parallel sliding along a plane at depth will cause downslope extension in the upslope half of a slide mass and shortening in the downslope half, consistent with observations. Displacement profiles that could be interpreted as rotational can result from sliding along such a plane, however careful analysis of surface deformation can be used to understand sliding at depth.

扇射探索法による採石場斜面の安定性評価

The calculation method was based on the fan-shoot searching technique which proposed to evaluate the stability of a quarrying slope. By using the simplified slice method theory, it was possible to deal with the discontinuous planes, as weak as cracks in a shear strength, and search for a slide plane of an arbitrary shape. When applying this method to the quarrying slope on site, it required the data on the strength of rock masses and the shear characteristics of cracked surfaces. In this study, the former were estimated from the rock testing and by the seismic prospecting, and the latter were obtained by the shear testing of rock samples carrying a simple crack. From the result of the stability analysis for the quarrying slope on site, a slide plane of high probability of occurrence was indicated.

Features of the real structure of lanthanum hexaboride single crystals

The real structure of lanthanum hexaboride single crystals was investigated using transmission electron microscopy (thin foil) and diffraction methods. Two structural defects were found, flat segregations and dislocations, having Burgers vector b‖〈100〉. Most of the dislocations are arranged in {100} planes, which may be slide planes for a simple cubic structure, but the dislocation loop configuration showed that during single-crystal growth their movement is not characterized by slide but by diffusion creep. It is shown that the main sourse of dislocations arising during growth of single crystals is generation by flat segregation which according to diffraction investigations has a different structure from both lanthanum hexaboride and tetraboride.

Subsurface Exploration Using Bucket Auger Borings and Down-Hole Geologic Inspection

The down-hole geologic inspection of 24 in. bucket auger borings has been a hands-on technique for collecting valuable geologic structural and lithologic detail in southern California investigations for over 35 yr. Although it has been used for all types of investigations for hillside urban development, it is of particular benefit in landslide investigations and evaluations. It has also been successfully used in fault investigations where trenching could not get deep enough to intercept the faults. The benefits of down-hole geologic inspection during detailed mapping of large landslide complexes with multiple slide planes are discussed in this paper. This paper is the result of numerous requests by city engineers, who have been faced with the monumental task of approving or disapproving urban development on ancient landslides within their jurisdictions. (Many of these areas have the best views.) Many of the geotechnical investigations of these massive landslide complexes have been very limited in their determinations of accurate landslide parameters and very deficient in proper engineering analysis while based upon this limited data. This has resulted in many cases where the geotechnical consultant erroneously concludes that ancient landslides don9t move and it is alright to build upon them, even though they have neither justified the landslide parameters, nor the slope stability or safety. In these cases, there was also no redundancy-in-design due to considering future landscape watering, future rainfall, and future earthquakes. These are a common problem throughout large portions of California and other mountainous states. Because this author and the many consultants contacted during the preparation of this paper were not aware of other publications regarding this method of collecting detailed geologic data, this author included the safety considerations, safety equipment, the cost and the Cal OSHA requirements for entering exploration shafts.

A Model of Landslide by Snowmelt Water Including the Classification and Generation

The present paper aims to describe the different types of landslide in relation to snowmelt water by a simple model depending on the behaviour of underground water and different apparent features of ground surface and plants. (1) Firstly two extreme types : liquid and solid ones, are proposed. In practice, mediate type appears and its mediateness is introduced. (2) Secondly a new classification of landslide is obtained by using of the segment length (after the slide) and water contents (before the slide) of the original ground. (3) Generation mechanism of slide should explane the mechanical balance and clay layer at the slide plane. A new model is proposed such that the clay layer may be grown by successive large snowmelt water among long years.

Pleistocene Suvero slide, Paola basin, southern Italy

The Suvero slide covers an area of about 225 km 2 in the Paola slope basin on the Eastern Tyrrhenian margin. The shape and lateral extent of the deposit reflect topographic confinement of the slide between the continental slope and a morphologic barrier formed by a margin-parallel slope ridge. No headwall or slide plane comparable in scale with the slide deposit were found, suggesting that quasi in situ deformation of semi-consolidated sediments took place when the failed materials reached the floor of the slope basin. The failure occurred downslope from a basement high originating from local uplift. Continued uplift, after the Suvero slide occurred, is documented by the presence of steep upper-slope gradients within the study area and by the presence of small-scale creep and failure events that postdate the Suvero slide.

Fundamental Problems of Landslide by Snowmelt

Fundamental discussion on the landslide in relation to snowmelt water is described.(1) Several types of classification of landslide is not systematic in special reference to the water behaviour. Practical slide appears frequently under deep snow circumstance which is fairly syste-matic more than the rain circumstance. (2) Slide generation is explained by the mechanical balance, whereas frequently clay layer, defined geologically, is observed at the slide plane. The writer proposes a new model such that a clay layer is grown in long years by successive snowmelt water, and then it is required that new discussions on the landslide. (3) The effect of snowcover on the slide is described on the two points of weight and snowmelt water.

Mass movements, geotechnical properties, and slope stability in the outer shelf—Upper slope, northwestern Aegean sea

Abstract Subbottom profiling (3.5 kHz) in the uppermost slope of the outer shelf of the northwestern Aegean Sea has shown downslope slumping and intense sediment deformation as well as a succession of microslumping within the Late Pleistocene delta sequences. Postdeposition bottom erosion by currents and the overconsolidated sediments (Cu/Po > 1) indicate the termination of deformations a long time ago. Deformation processes are estimated to have been active 18,000–10,000 B.P. Large‐scale active downslope deformations with clockwise sediment block rotation have affected the area as well. These longer‐period deformations are associated with regional neotectonics and older unconformities (i. e., Plio‐Pleistocene) as potential slide planes. Geotechnical properties reflect mainly textural variations and locally (within sapropelic layers) high organic matter content. Relatively high values of shear strength were measured (5–29 kPa) with intermediate sensitivities (2–5), whereas relatively low values of water c...

Landslide investigation utilizing electric cone penetration testing : French, J; Kropp, A In: Use of In Situ Tests in Geotechnical Engineering (papers to the Conference, Blacksburg, 23–25 June 1986)P529–545. Publ New York: ASCE, 1986 (ASCE Geotechnical Special Publication No 6)

A geotechnical investigation was conducted of landsliding at a hillside residential property to evaluate both the extent of the landslide and the stability of the fill materials as well as to provide recommendations for remedial work to stabilize the property. Conventional techniques were used to explore the site but were supplemented with cone penetration testing. The cone penetration work was performed to help locate the thin landslide slip planes and to evaluate the quality of the fill material present. By comparing the information from the conventional soil borings with the data from the cone penetration tests the primary slide plane was found, additional potential slide planes were located, patterns of subsurface variation were determined, and variability of individual lifts of fill materials was discovered.

Geometry of submarine slides in the Bowland Basin (Dinantian) and their relation to debris flows

Sedimentary slide deformation structures in the Lower Carboniferous (Dinantian) sediments of the Bowland basin show a spoon-shaped morphology with extension in the head region and compression in the toe. The particular structures developed depend on the rheological properties of the sediment involved. Slides in soft sediment have deformation distributed throughout the slide mass, with folding being the dominant deformation style. Slides within more lithified sediment have deformation concentrated along slip planes. Both types of deformation may be present within a particular slide, depending on diagenetic factors and the depth to which slide planes cut down. Disaggregation of slides to yield material for sediment gravity flows is explained by processes operating within the slide unit.

Structural changes in shear zones and slide planes of clays with different types of structural bonds

The study of shear zones and slide planes leads to the detailed characterization of the deformation process which depends mainly on the type of structural bonds between the particles. The results obtained by using a scanning electron microscope, show that the thickness of the zone of oriented clay minerals when shearing clays with phase contacts, is about 20–60 μm, while in clays with predomination of atomic (point) contacts is 30–150 μm. Almost the same thickness of this zone is observed in separate shear planes, forming one slide surface. In clays with close coagulation contacts the same zones have a different character and thickness, while in silts with distant coagulation contacts such zones are not observed.

Acoustic interpretation of Quaternary sedimentation and erosion on the channelled upper Laurentian Fan, Atlantic margin of Canada

About 1000 km of single-channel seismic-reflection profiles from a 50 km × 100 km area on the upper Laurentian Fan shows no evidence of the large slumps interpreted by previous workers in this area. Our detailed profile grid indicates that slump-like masses are commonly in depositional continuity with definite autochthonous sediments, and surfaces previously interpreted as slide planes are either facies changes or the result of valley-wall erosion. Only a few small slump blocks of relatively consolidated sediment are found on the uppermost fan. Acoustic-facies distribution shows a single Early (?) Pleistocene fan valley crossing the northeast part of the survey area with thick overbank sediments to the southwest. In the middle (?) Pleistocene this valley became incised. Its upper reaches then ceased to receive sediment, and a new valley was cut extending southward from the upper slope and intercepting the lower reaches of the old fan valley. This channel diversion was probably related either to the glacial excavation of the Laurentian Channel or to a major slump scar that formed east of the survey area. Most of the old abandoned channel was plugged by overbank deposits from the new master channel. Two other valleys farther west also developed at this time or somewhat earlier. In Late Pleistocene time, all three valleys were incised and more than 1 km of sedimentary material was stripped from much of the uppermost part of the fan, probably as a result of headward erosion of submarine canyons and general thalweg lowering.

Formation of Landslide and Its shape

The landslide face of plane shape is formed in the thin clay layer softened by the weathering of Tertiary layer. This clay layer is often called ‘latent slide face’, because the latent slide face has a basic factor in the landslide. Accordingly the landslide face is formed in the this part of clay by the occasion.Therefore, the length of landslide face in the latent slide face decides the shape of landslide, which is not a fortuitous resuit but the inevitable consequences. When the constants of shearing strength and physical properties of the clay layer are obtained by the soil tests, the length of landslide plane formed by the several causes is expressed by the following factors: that is, the average depth of the latent slide face h, the average inclination of the latent slide face θ, the coefficient of passive earth pressure in the upper part of the latent slide face kp, and the pore water pressure acting on the length of slide plane hw.It is very hard to measure the pore water pressure hw, when new landslide is caused by the heavey rain. Therefore, it is desirable that the shape of landslide plane should be used for the presumption of pore water pressure hw.

On the Process of Formation of the Slide Planes at Kuchinotsu Landslide Area (I)

On the Process of Formation of the Slide Planes at Kuchinotsu Landslide Area (I)