The effect of the seasonal temperature variation of the percolation water became evident when its influence was observed in the variations of the uplift pressure and flow in several rock mass foundations. Besides, it was possible to bring forward a new understanding about the rock mass deformation and its consequences. A theory is shown making an analogy between temperature and flow and the Darcy's laws becoming possible to solve and to understand the problem.
L'effet de la variation saisonnière de la temperature de l'eau de percolation est evidente quand cette influence a ete observee dans les variation des souspressions et debits aux divers massif rocheux de la fondation du barrage. En outre, a ete possible obtenir une nouvelle compreention, au sujet de la deformation, dans les massif rocheux et ses consequences. Une teorie est presentee faisant l'analogie entre la variation de temperature de l'ecoulement et la loi de Darcy, qui a rendu possible resoudre et comprendre Ie probleme.
Die Wirkung von saisonmassiger Temperaturanderung des Perkolationswasser ist deutlich geworden als ihr Einfluss in der Unterdruckspannung und Wasserfliessen in verschiedenen felsenmassivfundamenten beobachtet war. Ausserdem war es möglich ein neves Verstandnis ueber Felsenmassivverformung und ihre Folgerung zu entwickeln. Eine Theorie ist gezeigt, die eine Analogie zwischen desen Temperaturanderungeinfluss und das Darcygesetz macht und die Lösung und das verstandnis des Problemes ermöglicht.
This paper intends to call attention to the effect in rock mass foundation due to seasonal temperature variation of the percolation water. Previous papers presented by the author have various examples of this phenomenon and pave remembered here to show some variation in uplift pressure due to thermal variations in deep water percolation. Temperature was collected in four deep drains of Itaipu Dam. They present variation in temperature registered. Finally, a mathematic model presented compute its influence.
Andrade (1988a, 1988b, 1988c) has shown some Brasilians Dams where the piezometric values vary with the seasonal ambient temperature. On figure 1 and 2 is shown that values observed in Agua Vermelha and Ibitinga Dams - São Paulo, Brazil where piezometers attain to 28 meters variation. On the other hand, was in Itaipu Dam, (Andrade 1991), that has recorded variation in temperature. Figures 3,4 and 5 shows this variation of water percolation temperature in four deep drains at 3 and 6 meters in depth.
The author to analyses the values of the uplift pressure and flow in fractured rock mass foundation created a computerized method called Nodal Point Method (Metodo dos Pontos Nodais - MEPON). This method is based on the hypothesis that the flow happens trough main discontinuities that ocours in any kind of rock mass. This macroscopic hypothesis considers the rock mass foundation composed by subdomains. The contour are main discontinuities and the flow in this subdomains is consequence of the value of the pressure on the main discontinuities that form its limits. Those preferential ways of flow in MEPON have considered as a bar of a mesh. This bar that represents the main discontinuity has the form of that discontinuity; consequently it is not necessary to be a straight line. These discontinuities are identified through one field test called TRH - Teste de Registro Hidraulico (Hydraulic Register Test) (Andrade 1987), and present conductivity significantly enough if compared with subdomains discontinuities.