Based on the geological-geometric characterization of the basaltic rock at the site of a factory for chemical products situated in the Southern region of Brasil, and on results of a significant number of packer tests, the principal directions of flow were estimated, taking into consideration the intersection and the orientation of the joints and the amount of contaminant flow measured in each interval. The tests were performed using the multi-packer hydraulic multitest probe of IPT (HMTP) instrumented with an electric conductivity meter. A method of analysis for three-dimensional evaluation of the amount of contaminant flow in the area was proposed for future mitigation of the problem.
Base sur une caracterization geologique-geotechnique de la roche basaltique existant sur un site dune fabrique de produits chimiques situee au sud du Bresil et sur les resultants dún nombre significantif dessais du type packer, les directions principales d´ecoulement ont ete estimees en considerant l´intersection et orientation des joints et la quantite de contaminant mesuree sur chaque intervale d´essais. Ceux-ci ont ete realizes en utilisant une sonde multipacker developee au IPT - São Paulo (HMTP) instrumentee avec un mesureur de condictivite electrique. Une methode d´analyse 3-D pour l´evaluation du transport du contaminant sur ce site a ete proposee pour une future mitigation du problème.
Auf Grund der geologischen Struktur des Basalts auf dem Gelande einer chemischen Fabrik in Suedbrasilien und der Ergebnisse einer ansehnlichen Zahl von Pumpversuchen wurden die Hauptfließrichtungen bestimmt unter Beruecksichtigung des Kluftgefueges und der in jedem Intervall gemessenen Menge kontaminierten Wassers. Die Versuche erfolgten mit dem im IPT entwickelten Verfahren (HMTP) mit Mehrfachpackern und elektrischen Leitfahigkeitsgebern. Ein analytisches Verfahren zur dreidimensionalen Ermittlung der Mengen kontaminierten Wassers wurde fuer die kuenftige Befassung mit dem Problem entwickelt.
Civil engineering hydraulic testing performed in boreholes usually focuses on the use of the injection test (Lugeon test or water pressure test) to characterize permeability at the site of dams, mining or tunneling construction. For environmental purposes however, in view of the danger producing a strong gradient that can be a driving force for injecting the pollutant deeper into the media, it is more appropriate to perform pumping tests which withdraw the solute from the borehole. Traditional hydrogeological pump tests can be used and the hydraulic characteristics of the media can be determined either from the transient pressure response or from steady-state methods of interpretation.
However, the use of the hydraulic multi-test probe (HMTP) of IPT described later, has an advantage because local pumping tests can be quickly performed in fixed length intervals using alternating tests or tests adjacent to
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each other. The geometric characteristics of the rock joints in the borehole should be characterized first, using any available tool such as an impression packer or a borehole scanner device, or just registering (surveying) the geometrical data of the discontinuities appearing in the cores and in outcrops, whenever this is possible.
Although single pumping packer tests performed with the HMTP are not appropriate to direct investigation of the anisotropic directional hydraulic conductivity.
