Topografía para la construcción y control de túneles
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Fecha
2009-08
Autores
Soto Ocampo, Henry
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Universidad Nacional (Costa Rica)
Resumen
Dentro de la construcción de obras civiles, los topógrafos y geodestas constituyen un aporte muy importante en su diseño, construcción y control. En este orden de ideas, cabe referirse específicamente a la construcción de túneles, labor donde se concentran muchos elementos del conocimiento humano, puestos en práctica, para ejecutar obras de gran beneficio para la sociedad.
En este documento se explica, describe, evalúa y compara los conocimientos que el autor a través de la experiencia adquirida, tuvo en los proyectos hidroeléctricos Río Volcán, Don Pedro, Cote, Toro 1, Toro 2, Angostura y Cariblanco. Todos estos proyectos tienen obras de túneles.
Las características constructivas y de diseño en la construcción de túneles, no solo implica aplicar las técnicas y los conocimientos más modernos, sino que tiene una gran cota de esfuerzo físico y condiciones extremas de trabajo para los ejecutores. La responsabilidad de los profesionales es muy importante, porque el mismo trabajo los califica; hay poco margen para los errores, por los altos costos de ejecución, dadas sus repercusiones.
La preparación académica en este tipo de actividades, a nivel de centros de estudio, es frágil y la práctica casi nula, por las condiciones dadas. Sin embargo, son obras que se construyen en el país, y cada vez con más auge, de tal forma que debemos estar preparados para cubrir las necesidades del mercado. De ahí que este trabajo pretende traspasar y recopilar conocimientos que el autor adquirió durante 20 años, para que futuras generaciones de colegas, puedan cumplir su labor en forma exitosa.
Cuando se construye un túnel, se debe considerar como en cualquier obra civil, en la parte de posicionamiento, una red tridimensional de gran calidad, como referencia para los replanteos y controles. Su precisión, así como las correcciones geodésicas y topográficas, se definen según la magnitud del túnel, su longitud específica y en su sección. Al no poder tener controles exactos en el proceso, se debe arrancar con una red muy precisa, incluso de mayor exactitud que los cierres requeridos.
En la construcción de un túnel, la topografía no es un elemento más; es un protagonista de primer nivel, y con una de las mayores responsabilidades, para ubicar cada frente de trabajo. Los equipos que se utilizan no siempre son los construidos para estos fines. Por lo general, esta definición obedece a la magnitud del proyecto o los equipos disponibles para el resto de este, a no ser que se trate de un proyecto muy grande, donde sus finanzas estén dadas para la compra de equipos especializados, o bien que el ejecutor topográfico sea una empresa de trabajo constante en este tema, y tenga previamente, las herramientas topográficas especializadas.
Una vez definida, materializada y ajustada la red, se establecen los equipos y métodos por usar en el control y dirección de la excavación. Se debe considerar que las condiciones de trabajo son duras, de tal forma que los equipos seleccionados, deben ser de calidad, resistentes a la humedad, al agua, al polvo, entre otros, y deben tener la mayor precisión posible.
El personal, en lo posible, debe tener experiencia, así como estar en perfectas condiciones de salud, dado el medio extremo de trabajo, donde por lo general abunda el agua y el polvo. Las condiciones de iluminación y pureza del aire son pobres y se deben acoplarse a estas. Lo hecho dentro del túnel es muy parecido a lo realizado en cualquier otra obra; se llevan a cabo poligonales y nivelaciones, pero la gran diferencia es que no hay espacio para equivocarse. La materialización de los puntos es complicada, así como el ambiente de trabajo, en la parte física.
Una vez marcado el eje en las tres coordenadas para realizar las excavaciones, se deben realizar controles de poligonales y niveles, en forma constante, para tener los errores probables en un rango controlable.
En la mayoría de trabajos de replanteo, las teorías son similares; lo cambiante es la materialización de marcas, dónde se colocan y en que momentos del proceso, con qué frecuencia y qué equipo se usa. Sin lugar a dudas, el profesional debe analizar la disponibilidad de los equipos con los que cuenta y si con estos puede ejecutar los trabajos topográficos del túnel, con precisión y tiempo. Si no debe solicitar previamente los elementos mínimos necesarios para cumplir el objetivo. Una vez excavado el túnel, la precisión topográfica se reduce, porque existe una red con exactitudes y cierres conocidos, para poder replantear y controlar el resto de obras dentro de este.
Paralelamente a los trabajos de excavación, el personal de topografía debe hacer el levantamiento de secciones, para controlar y programar los volúmenes de excavación, de concreto, o de cualquier otro elemento de revestimiento del túnel. Además, se deben realizar todos los controles de deformación internos o externos del túnel, según lo defina el diseñador o propietario.
Finalmente para asegurar la inversión del proyecto, así como la seguridad de los usuarios, se deben hacer controles periódicos de deformaciones durante la existencia de la obra, con un programa bien estructurado.
Within the construction of civil works, surveyors and geodesists constitute a very important contribution in its design, construction and control. In this order of ideas, it is worth referring specifically to the construction of tunnels, work where many elements of human knowledge are concentrated, put into practice, to carry out works of great benefit to society. This document explains, describes, evaluates and compares the knowledge that the author, through the experience acquired, had in the Río Volcán, Don Pedro, Cote, Toro 1, Toro 2, Angostura and Cariblanco hydroelectric projects. All these projects have tunnel works. The construction and design characteristics in the construction of tunnels not only imply applying the most modern techniques and knowledge, but also involves a great level of physical effort and extreme working conditions for the executors. The responsibility of professionals is very important, because the work itself qualifies them; there is little margin for errors, due to the high costs of execution, given its repercussions. The academic preparation in this type of activities, at the level of study centers, is fragile and the practice is almost nil, due to the given conditions. However, they are works that are built in the country, and with increasing popularity, in such a way that we must be prepared to meet the needs of the market. Hence, this work intends to transfer and compile knowledge that the author acquired during 20 years, so that future generations of colleagues can carry out their work successfully. When building a tunnel, a high-quality three-dimensional network should be considered, as in any civil works, in the positioning part, as a reference for stakeouts and controls. Its precision, as well as the geodesic and topographic corrections, are defined according to the magnitude of the tunnel, its specific length and its section. Not being able to have exact controls in the process, it is necessary to start with a very precise network, even more accurate than the required closures. In the construction of a tunnel, topography is not just another element; He is a first-rate protagonist, and with one of the greatest responsibilities, to locate each work front. The equipment used is not always the one built for these purposes. In general, this definition obeys the magnitude of the project or the equipment available for the rest of it, unless it is a very large project, where your finances are given for the purchase of specialized equipment, or that the topographic executor is a company of constant work on this subject, and previously has specialized topographic tools. Once the network has been defined, materialized and adjusted, the equipment and methods to be used in the control and direction of the excavation are established. It should be considered that the working conditions are harsh, in such a way that the selected equipment must be of quality, resistant to humidity, water, dust, among others, and must have the highest possible precision. The personnel, as far as possible, should be experienced, as well as in perfect health, given the extreme environment of work, where water and dust are generally abundant. Lighting conditions and air purity are poor and must be coupled to these. What is done inside the tunnel is very similar to what is done in any other work; traversing and leveling are carried out, but the big difference is that there is no room for mistakes. The materialization of the points is complicated, as well as the work environment, in the physical part. Once the axis has been marked in the three coordinates to carry out the excavations, polygonal and level controls must be carried out constantly, in order to have the probable errors in a controllable range. In most stakeout work, the theories are similar; what is changing is the materialization of brands, where they are placed and at what moments in the process, with what frequency and what equipment is used. Undoubtedly, the professional must analyze the availability of the equipment they have and whether they can carry out the topographic work in the tunnel with precision and time. If you must not previously request the minimum elements necessary to meet the objective. Once the tunnel has been excavated, the topographic precision is reduced, because there is a network with known accuracy and closures, to be able to reconsider and control the rest of the works within it. Parallel to the excavation work, the topography personnel must survey sections to control and program the volumes of excavation, concrete, or any other element lining the tunnel. In addition, all tunnel internal or external deformation checks must be performed, as defined by the designer or owner. Finally, to ensure the investment of the project, as well as the safety of the users, periodic controls of deformations must be carried out during the existence of the work, with a well-structured program.
Within the construction of civil works, surveyors and geodesists constitute a very important contribution in its design, construction and control. In this order of ideas, it is worth referring specifically to the construction of tunnels, work where many elements of human knowledge are concentrated, put into practice, to carry out works of great benefit to society. This document explains, describes, evaluates and compares the knowledge that the author, through the experience acquired, had in the Río Volcán, Don Pedro, Cote, Toro 1, Toro 2, Angostura and Cariblanco hydroelectric projects. All these projects have tunnel works. The construction and design characteristics in the construction of tunnels not only imply applying the most modern techniques and knowledge, but also involves a great level of physical effort and extreme working conditions for the executors. The responsibility of professionals is very important, because the work itself qualifies them; there is little margin for errors, due to the high costs of execution, given its repercussions. The academic preparation in this type of activities, at the level of study centers, is fragile and the practice is almost nil, due to the given conditions. However, they are works that are built in the country, and with increasing popularity, in such a way that we must be prepared to meet the needs of the market. Hence, this work intends to transfer and compile knowledge that the author acquired during 20 years, so that future generations of colleagues can carry out their work successfully. When building a tunnel, a high-quality three-dimensional network should be considered, as in any civil works, in the positioning part, as a reference for stakeouts and controls. Its precision, as well as the geodesic and topographic corrections, are defined according to the magnitude of the tunnel, its specific length and its section. Not being able to have exact controls in the process, it is necessary to start with a very precise network, even more accurate than the required closures. In the construction of a tunnel, topography is not just another element; He is a first-rate protagonist, and with one of the greatest responsibilities, to locate each work front. The equipment used is not always the one built for these purposes. In general, this definition obeys the magnitude of the project or the equipment available for the rest of it, unless it is a very large project, where your finances are given for the purchase of specialized equipment, or that the topographic executor is a company of constant work on this subject, and previously has specialized topographic tools. Once the network has been defined, materialized and adjusted, the equipment and methods to be used in the control and direction of the excavation are established. It should be considered that the working conditions are harsh, in such a way that the selected equipment must be of quality, resistant to humidity, water, dust, among others, and must have the highest possible precision. The personnel, as far as possible, should be experienced, as well as in perfect health, given the extreme environment of work, where water and dust are generally abundant. Lighting conditions and air purity are poor and must be coupled to these. What is done inside the tunnel is very similar to what is done in any other work; traversing and leveling are carried out, but the big difference is that there is no room for mistakes. The materialization of the points is complicated, as well as the work environment, in the physical part. Once the axis has been marked in the three coordinates to carry out the excavations, polygonal and level controls must be carried out constantly, in order to have the probable errors in a controllable range. In most stakeout work, the theories are similar; what is changing is the materialization of brands, where they are placed and at what moments in the process, with what frequency and what equipment is used. Undoubtedly, the professional must analyze the availability of the equipment they have and whether they can carry out the topographic work in the tunnel with precision and time. If you must not previously request the minimum elements necessary to meet the objective. Once the tunnel has been excavated, the topographic precision is reduced, because there is a network with known accuracy and closures, to be able to reconsider and control the rest of the works within it. Parallel to the excavation work, the topography personnel must survey sections to control and program the volumes of excavation, concrete, or any other element lining the tunnel. In addition, all tunnel internal or external deformation checks must be performed, as defined by the designer or owner. Finally, to ensure the investment of the project, as well as the safety of the users, periodic controls of deformations must be carried out during the existence of the work, with a well-structured program.
Descripción
Soto Ocampo, H. (2009). Topografía para la construcción y control de túneles. [Tesis de Licenciatura]. Universidad Nacional, Heredia, Costa Rica.
Palabras clave
TOPOGRAFIA, TUNELES, GEODESIA, LEVANTAMIENTO DE PLANOS, TOPOGRAPHY, PROYECTOS HIDROELECTRICOS, TUNNELS