the surveys done by INGEOMINAS, IGAC, IDEAM, INVIAS, Universities, etc. .. October INVIAS – IGL () – Manual de Estabilidad de Taludes – INVIAS. INTRODUCCIÓN. Los muros de contención son estructuras que proporcionan estabilidad al terreno natural u otro material cuando se modifica su talud natural. FORMATO DEL MANUAL DE INTERVENTORÍA. Manejo Ambiental, actualizada por el INVIAS en el mes de abril de , los proyectos de .. pedraplenes, así como de los taludes de las excavaciones. Captación inconformismo de propietarios y empleados de la zona que pueden ver en riesgo su estabilidad.
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Skip to main content. Log In Sign Up. Colombia, Mexico, and a time ago Brazil, are the Latin American countries whose capital cities are located inside the country rather than in the coastal areas or nearby the coasts, as it happens in many other countries in the continent or in the world. The capital city, Bogota, the most crowded city and the economic and cultural center of a country with a central system instead of a federal one, is located in the Eastern Mountain Range, nearby the geometric center of the territory, m over sea level, km in straigth line from the Pacific Coast and km from the Atlantic Coast.
Routes in mountainous zones necessarily result in too long stretches relative to those seen at first glance in the map Figure 2. Therefore it was almost natural that the first airline company in the Americas was founded in Colombia in The savings in transportation costs should be reflected in investments compatible to road construction and conservation, both in the short and long term ranges.
Travel time is only part of the complex problem of transportation of goods and passengers, that also involves the study of the development of production areas, implementation of appropriate terminals, automotive equipment renewal, recreation planning, development of supply and demand centers, etc. Usually, most of the time, the best route is not necessarily the shortest one, in geographic terms, but rather that route that supplies the best and reliable service to the zone and to the purposes to which the route is destined.
In addition to allow an acceptable speed, the road should supply the maximum safety to users and estabiliead assurance of continued operation conditions throughout the year.
The earth surface, subject to the relentless geologic cycle, is continuously changing due to weathering processes changes due to climatic agentsto erosion and to mass movements, followed by deposition, densification, etc. Erosion and mass movements develop faster mmanual steep zones, while weathering is more marked in a tropical country, such unvias Colombia, than in countries of the temperate zone.
By contrast, vegetation tends to reduce the mechanical degrading rates and to slow intemperization. What it must be attempted is to obtain a new dynamic balance for the new road-zone system, such that it estabilifad a full road operation and the maximum safety for users estabiliad its working life.
It is possible to attempt to obtain this integration goal, at the maximum extent, of the road to its habitat, so to say, and in the other hand, to aim that the resulting unbalances could be controlled. When topography limits in such manner the alignment options, it is very important to bear in mind that any route chosen probably will be used for a much longer time than that of the common design periods employed in other regions years.
There exists also the predominant economic factor during the useful life of the road, in connection both with construction and operation costs, and also with the safety and conservation of the road and of the zone manuql which it has been implanted. The concept early discussed about travel time reduction, and on the other hand, the improvements gained in vehicle power, has resulted in that the emphasis put into road gradient reduction has been declining towards the importance related esttabilidad curvature improvement.
This, along with more versatile and efficient construction equipment, which allows shorter construction times and processes, have posed additional problems for mountain roads: If the above factors are not carefully considered and overcome, the designs and the resulting roads could be expensive, unsafe, and even unattainable or non-operable.
Also there will be no gain if the road has acceptable operation conditions, but an improper waste material disposal reduces the productivity of the zone it was intended to serve. Even though these physico-geological conditions act as an ,anual dynamic process, some factors could become individualized, to emphasize fundamental aspects of their influence: The tqludes mountain ranges are the result of independent orogenic convulsions that occurred in different geological ages, the last of which is currently evoluting.
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They are formed of materials of different origin, with sedimentary rocks prevailance in the East Mountain Range, igneous rocks in the Central Range, and marine sedimentary-volcanic rocks in the West range.
All the rocks had been subjected to the stresses accompanying mountain formation – which nowadays act locally in a significant way- which produced and produce rock weakening due to deformation, fracturing or nivias. In addition, as a result of dynamic effects due to active plate deformations, frequent seismic events are produced which further influence its behavior.
On the other hand, large zones, mainly in the Central Range, are covered by deep deposits of volcanic materials, resulting from the complementary effusion activity.
ESTUDIOS DE EXCAVACIONES SUBTERRÁNEAS EN MACIZOS ROCOSOS
Lastly, the three mountain ranges are significantly uplifted, thus actively stimulating relief destruction haludes. Rainy seasons, which are more intense, and over all, more long-lasting compared to those from other latitudes, combined with the factors mentioned above, had lead to a noticeable predominance of rock chemical alteration, and due to this condition, the weathering profile of the earth surface reaches significant depths, even though of variable magnitude, depending invlas the type of rock and on the topographic and denudation conditions of each location.
Meteoric rain, temperature, windbiologic and anthropic agents, when manuzl act on the high natural steep environment, intensify the denudating processes erosion and mass movementswhich in turn produce deep and extense colluvial and talus deposits of great heterogeneity and generally mankal condition.
In longer periods and due to changes in the base drainage level, the evolution cycle of alluvial valleys had left exposed broad and thick deposits of different recent ages at several hanging levels above the actual river network.
The above factors had made that nearly every type of soil and rock can be found in Colombia: There are residual soils of all kinds, expansive and dispersive clays, peats; allophanic, haloisitic, kaolinitic and lateritic soils, etc.
Colombia, therefore, can be considered as a huge and large-scale varied geotechnical laboratory. Such significant variety of geotechnical materials and of physical and climatic conditions, together with the need for a fast economic development, entails a permanent yaludes to Colombian geotechnics, which the country is to face with the sparce available resources and has forced the country to solve its geotechnical problems in a somewhat fast, although disordered, way.
Due to this situation in Colombia, as well as in other Andean countries, attempts to counteract land instability only have allowed as yet, to develop some extent of qualitative or semi-quantitative perception about the causes and incidence, failing to reach an actual quantification of the effects thereof.
Therefore, one can say that a lot of effort is required to gain the knowledge necessary to cope with this type of problems on a systematic and economic basis, with achievements equivalent to those other etsabilidad in the world are gaining i. Schuster,Cruden and Fell, Most foreign technologies, however, have been developed in countries that have different environmental and socio-economic characteristics than those existing in Colombia, and therefore, they are not fully applicable to Colombian conditions, unless a careful process of adaptation taludse is previously made.
Additionally, df infrastructure wstabilidad yet deficient and there is neither a centralized management nor a unified methodology to face and control such phenomena.
Due to the ongoing shortage of resources allocable to country development, it is necessary to face with the problems using methodologies and systems consistent with the Colombian physical and social conditions.
Paradoxically, when resources are scarce, it turns out to be more necessary and nearly indispensable to optimize the processes and refine, as far as possible, estaabilidad and technological tools, inasmuch as conscious or unconscious squandering may lead to irreversible negative situations. In this paper some definitions are discussed and a general proposal of xe to assess landslide hazards for planning is presented, which if stepwise implemented, could contribute to alleviate risks from mass movements in Colombia.
Conceptually it can be expressed as: From 2a one can also deduct that risk always has a finite value if hazard exists, except when exposure E is nil, in which case risk would also be nil. Theoretically, the hazard component should be evaluated in terms of destructive potential, the element strength in terms of compatible units with the absorption of this potential by the element without damage extabilidad the exposure as a function of the spatial and temporal relative position of the elements involved in relation with the distribution of the magnitude of the hazardous phenomena.
Due to this complex relationships, there are estabioidad degrees of hazard and vulnerability and consequently, of risk.
estailidad Landslides can be considered as second or third-order events because they are produced by natural or artificial phenomena which are the causes or first-order events Figure 3. Different magnitudes or intensities of these causes produce landslides with variable hazard levels, depending upon material and slope susceptibility and upon the potential energy of the susceptible mass as related to the place under consideration.
Mass flows and avalanches can be looked as third or fourth-order events, because usually they are consequence of landslides or of landslide dam failures.
Landslide potential energy is controlled both by internal properties, such as mass brittleness Bishop, deformability, residual strength i. Skempton, and volume; as well as by external factors: Usually landslide internal and external factors are not easily separated and their evaluation and relationships are complex. For this reason there are not nowamnual to the Author, landslide quantitative hazard complete models expressed in terms of probabilities of destructive potential, and the study presented in this paper is an attempt into this tsludes.
Because landslides are high order events, their maximum probability does not coincide with the maximum magnitude of the triggering event, neither a slope failure is always a tauldes.
To get from the triggering events to the hazard, complex probabilistic paths have to be followed. Therefore, to obtain reasonable values of probabilities, simplifications inviaa assumptions have to be made.
Additionally, development of this general methodology involves several degrees of spatial and temporal coverage, both in details and precision, together with the appropriate cost and time allowance for these studies.
On the other hand, in the world, and of course at country level, it is necessary to develop procedures, methods and reliable scales in order to have a quantified picture of risks resulting from mass movements. Also detailed studies of five landslides were completed, from field investigations to evaluation of remedial measures and drawings and specifications for construction. Almost all the results of this study were presented at the 1st.
Southamerican Symposium on Landslides SCG, and also the methodology delineated before was a by-product of the experience of the Author in this research. Different ranges of variability are assigned to each factor according to its influence in slope stability. The eight original parameters, their index ranges and their factors were as follows: Compressive strength, rock mass fracturing Soil: As the method was applied, several modifications were done, among which the main ones are: Also the addition of the intrinsic parameters was classed as a Susceptibility Index, and the CE indexes, properly manipulated over the area, and treated stastistically, lead to a Relative Mass Movement Hazard Index Figure 5.
This methodology is thus, a big effort in geomorphological deconvolution and in this paper only a very short account will be presented, which perhaps does not reflect all the potential and usefulness of it. Therefore the interested reader should read the references at the end of the paper.
This methodology, proposed and developed by the Colombian engineer Tomas Ed in papers from tobesides its use to perform stability evaluations on a large scale basis, allows, for the materials of the hillslopes, the estimation of their geotechnical parameters such as density and phase relationships, strength and deformation parameters for both the mass and the elements that constitutes such slopes, and also the so called pressurization parameters for the mass, which include, both present and relict, positive, negative and excess fluid pressures.
Because this surface is the interface of the earthen material with its environment, due to physical and thermodynamic reasons, it should be, on average, in dynamic equilibrium with its surroundings. For these reasons, Shuk postulates Shuk,, that this function should correspond to an average factor of safety of 1. Estabilivad a given population of natural slopes, population defined as composed of slopes belonging to the same geological formation, it has been found that the values HLF and LLF or HLD and LLD also are related by the basic function 1but with lower correlation coefficients.
But in this case of populations, the stability criterion suffers an inversion, because the hillslopes higher and steeper than the average would be the stronger and therefore the more stable ones. Also, if limit values of HLD and LLD of all the slopes in a region a universeirrespective of its origin, are examined, they also comply with the basic function, fact that insinuates a fractal characteristic of this function In conclusion, with the measurements of the limit values of hillslopes it is possible to deduct statistically Factors of Safety FS and Failure Probabilities pF of the individual hillslopes, relative to a population or to an universe.
As in all statistical methods, the larger the data base, the better the approximation of the relative values to the true ones.
Furthermore, Shuk found that in a single hillslope, the Present Envelope always lied below the results of conventional analyses and that the differences in height were almost constant. This led Shuk to the deduction that the so called Present Envelope estanilidad corresponded really to long term stability and that the conventional analyses represented short term stability conditions.
Therefore two additional Envelopes emerged, depending invuas the time span for which the stability was going to be evaluated: With all this background, it is possible to calculate edtabilidad factors of safety and relative failure probabilities of individual slopes as referred to an universeas follows: However, to obtain numerical values of the different time spans, it is necessary to adopt one of them. In the andean Colombian estabi,idad the maximum annual rainfall cycle is between 4 taluees 6 years, very similar to the short cycle of 4.
Because of that, this period has been usually adopted as the short term time span for this region. For the very rainy zones of Western Piedmont the maximum annual rainfall cycle is between 9 and 14 years, similar to the basic Finally, with critical rain and wstabilidad data and with wstabilidad Total Probability Theorem eq.
It should be noted that the reliability of this methodology relies strongly on the accuracy of the topographic maps, and also on the relationship of this accuracy with the relief features. For the Colombian mountainous environment, aerophotographic restitutions to 1: Also, since natural processes are dynamic, it should be remembered that the evaluation is done for the date of the map and that the use of maps of different dates for the same evaluation will distort the results.
A suggested general procedure to obtain Mass Movement Relative Hazard Maps, which has been used by the Author, includes the following activities, not necessarily listed in chronological order: Alternatively the SSE and NSM maps can be calibrated independently with the Process Map and then contrasted to produce the final map, but the initial procedure is recommended.
As a result, urgency for a deep improvement of the road, nowadays under way, was identified. Panamerican Symposium on Landslides – Vol. Paipa ColombiaAugust. Conference on Structural Safety and Reliability – Vol. Unpublished report for the National Fund for Development Studies.
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