Showing papers in "Bulletin of the International Association of Engineering Geology in 1977"
TL;DR: In this paper, a tentative correlation between rainfall and landslides was established, and the drawing of nine danger charts, one for each region, defined four zones of increasing risk of generation of landslides and, if conveniently utilized by Government agencies, might constitute a warning element.
Abstract: This paper contains an analysis of the precipitation records of nine regions in Brazil which were, in the last years, the stage of catastrophes at the time of intense rainfall events. A tentative correlation between rainfall and landslides was then established. The final result of this correlation is the drawing of nine “danger charts”, one for each region. These charts define four zones of increasing risk of generation of landslides and, if conveniently utilized by Government agencies, might constitute a warning element, making possible a minimization of the consequences of these natural phenomena.
87 citations
TL;DR: In this article, the authors present a review of the most commonly used corrective measures, such as modification of the slope profile by excavation and filling, and drainage, with particular atteniion being given to horizontal drains and to trench drains.
Abstract: The General Report consists of three parts. In Part 1, the various types of corrective measures are briefly reviewed. Attention is then concentrated on the two, most used measures; modification of the slope profile by excavation and filling, and drainage. An analysis is made of the optimum positioning of corrective cuts or fills, making use of the influence line concept, borrowed from structural engineering. In this way a neutral point, neutral line and neutral zone are defined for circular and non-circular landslides and for various values of B with respect to the applied change in total stress. Drainage is then discussed in more detail, with particular atteniion being given to horizontal drains and to trench (and counterfort) drains. Performance data for trench drains in the U.K. are then reviewed and analysed. From this a tentative basis for design is developed. In Part 2 the papers contributed to Theme 3 of the Symposium are reviewed. The clogging of drainage systems by siltation or by geochemical effects, is also discussed. Finally, in Part 3, some suggestions are made as to the desirable directions of future research. An extensive list of references is provided.
84 citations
TL;DR: In this article, a series of factors may be responsible for the origin of these deformations, and various opinions on the movement mechanism of these slope deformations have been expressed and schematic cross-sections drawn.
Abstract: Some of the high mountain slopes are affected by deep-reaching gravitational deformations. Significant geomorphological manifestations of these deformations were described from many high mountain ranges of the world. The type of deformation depends on the geological structure of the slope. During the last ten years various opinions on the movement mechanism of these slope deformations have been expressed and schematic cross-sections drawn. Dips of slope deformations are given within the range of 18o to 50o. A whole series of factors may be responsible for the origin of these deformations. Deep-reaching gravitational deformations can cause serious economic damage.
80 citations
TL;DR: In this paper, a simple method of determing relative landslip risk in clay slopes for land use planning and insurance purposes is proposed which combines plasticity index, water conditions, slope angle, slope complexity and land use.
Abstract: There is a need for a simple method of determing relative landslip risk in clay slopes for land use planning and insurance purposes. A method is suggested which combines plasticity index, water conditions, slope angle, slope complexity and land use. The formulation is described and discussed and some examples from Tasmania are given.
54 citations
TL;DR: The study and mapping of the landslides triggered by the seismic shocks in May and in September 1976 were carried out using systematic photointerpretative observations completed by field studies as discussed by the authors, which consist mainly of rockfalls which frequently took place as a result of the reactivation of phenomena which existed before the earthquake.
Abstract: The study and mapping of the landslides triggered by the seismic shocks in May and in September 1976 were carried out using systematic photointerpretative observations completed by field studies. The landslides consist mainly of rockfalls which frequently took place as a result of the reactivation of phenomena which existed before the earthquake; the relationship between the landslides and the geotectonic and morphological conditions of the slopes is discussed.
39 citations
TL;DR: In this paper, a model of failure mechanism can be assumed on the basis of contractant-dilation behaviour of rock masses, which correspond well with geomorphological manifestations of 138 deformation cases.
Abstract: Deep-seated creep deformations of slopes attaining kilometres in dimensions occur quite often even in the metamorphosed rocks and granitoids forming the crystalline core of the Tatry and Nizke Tatry Mts. They have a form of gravitational folding and fan-like disintegration of mountain slopes. In both cases, however, a similar model of failure mechanism can be assumed on the basis of contractant-dilation behaviour of rock masses. To this model of deformation correspond well the geomorphological manifestations of 138 deformations we detected. These slope deformations can cause serious economic losses.
34 citations
TL;DR: In this article, the role of vegetation is presented under mechanical aspects as well as those related to the hydrologic balance, and the authors consider that only the establishment of a multi-disciplinary approach to this subject will further the knowledge of the humid tropical environment, permitting a more rational use of the natural resources.
Abstract: In this paper, the personal experience of the authors on the behavior of the vegetation in slope stability, is added to the scarce bibliography dealing with the subject. The pending questions about the “natural vegetations-mass system”, under the action of Brazilian climatic conditions, are pointed out. The role of vegetation is presented under mechanical aspects as well as those related to the hydrologic balance. The authors consider that only the establishment of a multi-disciplinary approach to this subject will further the knowledge of the humid tropical environment, permitting a more rational use of the natural resources.
30 citations
TL;DR: In this article, a few models of the landslide mechanism due to water level fluctuation in reservoirs are presented and the instances of recent slope failures around reservoirs are shown, and a few instances of such failures are discussed.
Abstract: In Japan thorough investigation has been lately enforced for the slope stability threatened by water level fluctuation in reservoirs. In this paper, a few models of the landslide mechanism due to this cause are presented and the instances of recent slope failures around reservoirs are shown.
23 citations
TL;DR: In this paper, a long-term project for a landslide inventory has been initiated in Calabria, where slope instability constitutes a major geological hazard, and a computer-based data bank of slope instability phenomena has been tested in two zones characterized by different geological and geomorphological conditions.
Abstract: A long-term project for a landslide inventory has been initiated in Calabria, where slope instability constitutes a major geological hazard. This project that involves the building up of a computer-based data bank of slope instability phenomena, has been tested in two zones characterized by different geological and geomorphological conditions. Univariate and multivariate statistical analysis indicates that landslide morphometric and typologic attributes are highly dependent on the geologic and geomorphic features of the area where slope failure occurs. Moreover, although most of the morphometric attributes of landslides affecting these two zones differ significantly, their relationships expressed in terms of correlation coefficients show an overall similarity. Lastly, a linear combination of these attributes can discriminate most of the landslides occurring in these two investigated areas.
20 citations
TL;DR: Au-dela d'un simple inventaire des mouvements de terrain anciens ou recents tels que les glissements, les ecroulements, les effondrements,…, the cartographie ZERMOS se propose d'etudier la distribution probable de ceux-ci dans l'espace.
Abstract: Au-dela d’un simple inventaire des mouvements de terrain anciens ou recents tels que les glissements, les ecroulements, les effondrements,…, la cartographie ZERMOS se propose d’etudier la distribution probable de ceux-ci dans l’espace. A partir d’informations objectives dont les plus significatives sont reportees sur les cartes (figures noirs lies a la morphologie, a la dynamique des versants, au drainage,…) son objet est d’indiquer par un zonage de couleur (rouge-orange-vert) les secteurs d’instabilite reelle ou potentielle et les dangers qui menacent ces terrains. S’inscrivant dans un cadre d’interet national, visant a mieux se proteger contre les risques naturels, cette cartographie ZERMOS, de facture nouvelle, devrait s’affirmer dans les prochaines annees et tendre vers des documents unifies.
20 citations
TL;DR: For the determination of the time dependent friction behavior on rock joints laboratory tests (in principle direct shear test) are conducted as mentioned in this paper, and the results show that the friction resistance depends on shear rate and relative movements.
Abstract: For the determination of the time dependent friction behaviour on rock joints laboratory tests (in principle direct shear test) are conducted. “Opalinuston” as a weak rock was used as test material. The tests are carried out under controlled strain conditions at different shear rates. The results show that the friction resistance depends on shear rate and relative movements. For constant relative movements and a constant normal stress a logarithmic relation between friction resistance and shear rate results. By determining the dependence of the viscoplastic friction on relative movement a creep curve can be deduced describing the friction behaviour of a joint in the examined time range.
TL;DR: In this article, the authors defined the centers of gravity of the slide mass both before and after failure and found that the slope of the line joining the centres of gravity was equated to the apparent angle of friction.
Abstract: On January 9, 1965, the Hope slide occurred in the Casade Mountains of British Columbia and buried 4.5 km of B.C. highway number 3. Two minor earthquakes, with epicentres in the vicinity of the slide, are cited as the most probable cause of failure. Analysis of the pre and post slide topography defined the centres of gravity of the slide mass both before and after failure. The slope of the line joining the centres of gravity was equated to the apparent angle of friction of the slide path. This slope was found to be very similar to the value of the ultimate friction angle in shear tests on the slide debris.
TL;DR: In this paper, a general report summarizes recent studies concerning gravitational deformations of natural slopes and their origin in different factors: deep creep, unloading due to errosion or weathering along faults, permafrost thawing.
Abstract: This general report summarizes recent studies concerning gravitational deformations of natural slopes. Many translational rotational, and more complex movements are briefly discussed with respect to rock properties, slope geology, geometry and history. A number of marginal block slides is outlined, their origin being connected with different factors: deep creep, unloading due to errosion or weathering along faults, permafrost thawing. Cases of cambering and valley bulging are reported, ascribed mainly to glaciation and subsequent unloading of the ice-sheet. Special attention is paid to some studies of natural slopes instrumented as test sites. A comprehensive bibliography is given.
TL;DR: Deep-seated gravitational slope deformations in neovolcanic mountain ranges in Slovakia arise in places where brittle volcanic rocks (andesites, basalts and their pyroclastic material) rest on plastic Paleogene or Neogene rocks as discussed by the authors.
Abstract: Deep-seated gravitational slope deformations in neovolcanic mountain ranges in Slovakia arise in places where brittle volcanic rocks (andesites, basalts and their pyroclastic material) rest on plastic Paleogene or Neogene rocks. Where such a structure is associated with tectonic elevations, block rifts, bulging phenomena, block fields, landslides, rockfalls and earthflows occur. The deformations are most frequent on the peripheries of the Vtacnik and the Kremnicke hory Mts. (on an area of 186 sq.km), on the periphery of the Slanske vrchy Mts. (120 sq.km). The deformations cover smaller areas in other mountain ranges. Active block movements are a serious geotechnical problem, since they are most dangerous in Slovakia.
TL;DR: In this article, the authors deal with gravitational deformations in areas built of Mesozoic rocks, included in the area of high mountain ranges of the West Carpathians, and deal with the most frequent are ceep slope deformations with the character of disintegration of mountain ridges and of slopes with a system of rock rifts and blocks distributed over the alpinotypically folded soft bedrock.
Abstract: The authors deal with gravitational deformations in areas built of Mesozoic rocks, included in the area of high mountain ranges of the West Carpathians. These areas are affected by slope movements of all the four principal groups in the sense of the classification by A. Nemcok, J. Pasek, J. Rybař (1972). In total 410 deformations have been recorded. Most frequent are ceep slope deformations with the character of disintegration of mountain ridges and of slopes with a system of rock rifts and blocks distributed over the alpinotypically folded soft bedrock. An example of such deformations is the deformation on Sivý vrch hill and Radove skaly in the Zapadne Tatry mountains, which is described in detail.
TL;DR: In this paper, three idealistic models for the calculation of avalanche movements are presented, and the flow resistance of these two movements can be calculated approximately, given the steady uniform flow conditions with a constant density.
Abstract: For the calculation of avalanche movements, three idealistic models will be presented. First, the “Gliding block motion” with a constant friction coefficient. In this case the velocity can be estimated from the straight energy-line. Next, are the two turbulent motions, the “Rolling motion” and the “Scattering motion”. The flow resistance of these two movements can be calculated approximately, given the steady uniform flow conditions with a constant density. These flow coefficients are used to demonstrate the material properties which play a part in real mountain slides and avalanches.
TL;DR: In this paper, two basic modes of colluvial soil accumulation on hillsides are identified: 1) on rock benches; and 2) in swales, and they were assumed to be stable and to have developed under periglacial conditions.
Abstract: The Applachian Plateau Physiographic Province of the United States has severe landslide problems that are attributed primarily to steep topography and thick colluvial soils. Two basic modes of colluvial soil accumulation on hillsides are identified: 1) on rock benches; and 2) in swales. The large colluvial masses, unless disturbed by construction activity, were assumed to be stable and to have developed under periglacial conditions. However, processes of colluvial slope development and a recent landslide, activated by abnormally high precipitation at McMechen, indicate that such colluvial masses form continuously and do not require periglacial conditions to explain their existence.
TL;DR: In this paper, the analysis of about 9,000 slope deformations registered in Czechoslovakia shows that each deformation is related to a geologic-tectonical structure favorable for slope movements.
Abstract: The paper deals with geological-tectonical structures on which the slope movements take place. The analysis of about 9,000 slope deformations registered in Czechoslovakia shows that each deformation is related to a geologic-tectonical structure favourable for slope movements. Described are three types of such structures.
TL;DR: In this paper, the relation between component elements of earth masses in these types of landslides is shown and two types of complex landslides (stepped and transforming) are described.
Abstract: Involved landslides on slopes frequently result from combination or superposition of simple landslides or their change during the process of displacement Two types of compound landslides (bead-like and multi-storeyed) and two types of complex landslides (stepped and transforming) are described The relation between component elements of earth masses in these types of landslides is shown
TL;DR: In this paper, two well exposed virtually horizontal (measured in the direction of sliding) bedding planes in the Hampshire cliffs of England are described and reasons for their utilisation during shallow landsliding discussed.
Abstract: The widespread occurrence and problems associated with beeding plane slip surfaces are described. Two well exposed virtually horizontal (measured in the direction of sliding) bedding planes in the Hampshire cliffs of England are described and reasons for their utilisation during shallow landsliding discussed. These two examples provide a striking demonstration of the extent to which a preferential control on the form of landsliding can be exercised by such surfaces irrespective of their level within the slope profile.
TL;DR: The conditions necessary for the origin of block landslides are: (1) geological and lithological slope structure corresponding to a two-layered medium with a brittle upper layer and a plastic lower layer; sufficient thickness of the upper layer in order to transfer loads to the lower one, which generate irreversible deformations in the latter, and to form blocks; (2) conditions for plastic deformations and lateral spreading of masses of the lower layer as mentioned in this paper.
Abstract: The conditions necessary for the origin of block landslides are: (1) geological and lithological slope structure corresponding to a two-layered medium with a brittle upper layer and a plastic lower layer; sufficient thickness of the upper layer in order to transfer loads to the lower one, which generate irreversible deformations in the latter, and to form blocks; (2) conditions for plastic deformations and lateral spreading of masses of the lower layer. These conditions serve as criteria for the forecasting of the locations of block landslides. The geological structure of some parts of Bulgaria is favourable for their origin. The determined low speeds of contemporary movements of the block landslides provide the possibility to use the affected territories for construction and other economic activity.
TL;DR: In this paper, a procedure of geophysical methods, serving for the areal limitation of the collapsed parts of slopes, for the depth limitation and determination of the sliding zone course and for the estimation of the existence of slope movements as well as the tracing of their development, is described.
Abstract: The paper reviews geophysical methods used for the investigation of slope failures and describes a procedure of geophysical methods, serving for the areal limitation of the collapsed parts of slopes, for the depth limitation and determination of the sliding zone course and for the estimation of the existence of slope movements as well as the tracing of their development.
TL;DR: In this paper, an approach to engineering geological assessment for urban planning and development is presented, where the engineering geological investigations for the urban planning of Santa Cruz de Tenerife (Canary Islands) are used as an example.
Abstract: An approach to engineering geological assessment for urban planning and development is presented. The engineering geological investigations for the urban planning of Santa Cruz de Tenerife (Canary Islands) are used as an example.
TL;DR: The causes of the origin of landslides on banks of water reservoirs are summarized and the methodology of their investigation including the prediction is presented in this paper, where an example is given of bank deformations of the Nechranice reservoir in North-Bohemia, constructed in Miocene sediments liable to sliding.
Abstract: The causes of the origin of landslides on banks of water reservoirs are summarized and the methodology of their investigation including the prediction is presented. An example is given of bank deformations of the Nechranice reservoir in North-Bohemia, constructed in Miocene sediments liable to sliding.
TL;DR: In this article, the authors present a systematique des mouvements de terrain sur la carte Saint-Jean-de-Maurienne (SJDM) with a population of 1∶50 000 (560 km2).
Abstract: L’etude systematique des mouvements de terrain sur la carte Saint-Jean-de-Maurienne au 1∶50 000 (560 km2) a permis de dresser 225 fiches descriptives de cas et d’analyser les principaux facteurs geologiques et morphologiques de leur declenchement. Cet important travail est brievement decrit.
TL;DR: In this paper, a method of systematic inventory of landslides and other dangerous slope deformations is described, which has been adapted to the storage of computer memory in the Geological Data Base system.
Abstract: A new method of systematic inventory of landslides and other dangerous slope deformations is described, which has been adapted to the storage of computer memory in the Geological Data Base system. The results of the evidence obtained in the field work are plotted on a map, and are recorded on 2 pages of a form.
TL;DR: In this article, it was shown that in addition to the acceleration of the vibrations caused by blasting the displacement amplitude has a substancial influence on the origin of a slope movement and its limit values are given in relation to the jointing of the rock massif.
Abstract: The man-made landslides can also be caused by blasting operations. Under unfavourable conditions e.g. if the strata of a rock massif dip into the slope, the damage can be considerable. It is shown that in addition to the acceleration of the vibrations caused by blasting the displacement amplitude has a substancial influence on the origin of a slope movement and its limit values are given in relation to the jointing of the rock massif.
TL;DR: In this paper, it was shown that the damage to terrain and buildings which occurs on the flanks of subsidences cannot always be explained by the conception of a sinking trough model.
Abstract: Damage to terrain and buildings which occurs on the flanks of subsidences cannot always be explained by the conception of a sinking trough model. Such damage shows features related to slope sliding. An exact proof of the process on the basis of soil mechanics will be given in subsequent papers.
TL;DR: In this article, it is shown from extensive geological investigations completed since 1934 that the permanent landslides originate at the contact between loesses and Tertiary clays and that the direct neighbourhood of subsurface watersheds and the lithological differentiation of the loesses are responsible for the lack of direct correlation between precipitation, ground water oscillations and the somewhat delayed slide movements.
Abstract: It is evident from extensive geological investigations completed since 1934 that the permanent landslides originate at the contact between loesses and Tertiary clays. The direct neighbourhood of subsurface watersheds and the lithological differentiation of the loesses are responsible for the lack of direct correlation between precipitation, ground water oscillations and the somewhat delayed slide movements. Site investigations, particularly by universal probe and Dutch penetrometer, provided relatively accurate results for calculating the stability of slopes by the Bishop and Nonveiller methods. The calculated results coincide very well with field observations.
TL;DR: In this paper, the authors dealt with several aspects of field investigation, particularly with the study of stress and hydrogeological conditions in slopes, and paid special attention to the progressive disturbance of slopes, mainly in the presence of major residual stresses.
Abstract: The report deals with several aspects of field investigation, particularly with the study of stress and hydrogeological conditions in slopes. Some questions concerning the shear strength are discussed. Special attention is paid to the progressive disturbance of slopes, mainly in the presence of major residual stresses. In connection with this the differences in the safety factors of slopes are considered.