Auscultación deformacional por métodos geodésicos clásicos de presas de hormigón de gravedad

Resumen

During a four-year cycle, leveling and collimation readings were performed in three straight-line gravity dams, with a height from foundations close to 20 meters. The reliability of many series of these readings combined with a high instrumental precision and the maintenance of the decisive human factor, allows to deduce the determinant influence of the environmental thermal factor on the vertical movements, as well as the secondary influence, with respect to the hydrostatic thrust, on the Horizontal movements. With the objective of proposing a common behavioral model for gravity concrete dams, with physical significance for their parameters, which reproduces the expected movements of the coronation with respect to the foundation in gravity dams, we propose an annual thermal environmental law Formed by two sinusoids coupled and adjusted, in the valley temperatures and average monthly crest, of the place of the location of each prey. The environmental thermal law is adopted for reservoir water in contact with the wet face of the dam, and insolation, the daily cycle of temperatures and the flow of heat through the foundation are neglected. It dampens and delays the annual cycle temperature, as it flows through the dam body, perpendicular to its respective surface, depending on its only parameter: diffusivity. The average temperature of the solid concrete of each day of the year, in the vertical of each leveling control, is determined from the nearest wet or dry surface, for a height of each block limited by contact with the ground, and The magnitude of its displacement by the constant of proportionality: the coefficient of thermal expansion. The movements of each spot are calculated with respect to the external reference, consisting of a leveling nail, and origin campaign, and its sum is plotted against the environmental annual temperature law, which is shown in a loop diagram. This graph will make it possible to predict the movements of the dam before each leveling campaign, which is considered basic to obtain reliable data and, therefore, the possibility of studying their future deviations due to other minor effects.