SIMPA - REZUMAT
  • Director proiect: dr. ing. Constantin Radu GOGU
  • Contract de finantare: 218/23.07.2010
  • Organism intermediar: Autoritatea Nationala pentru Cercetare Stiintifica
  • Beneficiar: Universitatea Tehnica de Constructii Bucuresti
  • Perioada de implementare: iulie 2010 – iulie 2013
  • Valoare finantare nerambursabila: 3.826.978


Mediile sedimentare (sedimentele aluvionare, delte, etc.) sunt in general acvifere foarte importante datorita caracteristicilor ca: permeabilitati mari, capacitati de stocare, interactiunea cu apele de suprafata, etc. Expolatarea acestor tipuri de acvifere este semnificativa deoarece, printre alte motive, aceste acvifere sunt usor accesibile (in general nu este nevoie de sisteme complexe de captare si in cele mai multe cazuri sunt suficiente puturi si/sau foraje intre 10 – 100m adancime). In acelasi timp accesibilitatea acestor acvifere contribuie la faptul ca acestea au o vulnerabilitate crescuta. De aceea, pentru a asigura si a garanta timpul si utilizarea acestor resurse este necesar un management hidrologic adecvat. Gestiunea corecta a acestor acvifere se poate realiza numai prin modelare hidrogeologica.

Modelele ce stau la baza gestiunii acviferelor permit conceptualizarea si cuantificarea proceselor hidrogeologice si simuleaza o serie de scenarii precum secete, exploatarea resurselor, evolutia calitatii apei, comportamentul poluantilor in acvifer, interactiunea intre lucrarile subterane conditionate de comportamentul hidraulic si geomecanic al terenului, etc.

Pentru ca aceste modele sa ofere rezultate corecte este necesar ca acestea sa reproduca in mod corect procesele hidrogeologice. Totusi, se stie faptul ca mediile sedimentare sunt extrem de eterogene, ceea ce este si un paradox deoarece de obicei se folosesc modele foarte simplificate bazate pe ipoteza omogeneitatii unor zone mari.

S-a demonstrat faptul ca este posibil sa se utilizeze modele omogene reprezentative daca se ofera informatii despre comportamentul acviferului relationat de resursele de apa (Meier et al. 1998). Totusi, in situatia in care conectivitatea este esentiala, aceste modele sunt complet necorespunzatoare pentru caracterizarea problemelor legate de poluare si remedierea acestora (Zinn & Harvey, 2003; Wen & Gomez-Hernandez, 1996; Knudby & Carrera, 2005).
Modelarea in detaliu a acestor medii este foarte complexa din doua motive: primul este legat de eterogenitatea mai sus amintita a mediului, iar cel de al doilea rezida din faptul ca instrumentele pentru manevrarea datelor (geologice si hidrogeologice) si pentru implementarea acestora in modele hidrogeologice, nu sunt inca dezvoltate.

Pentru ca modelul hidrogeologic sa fie solid si sa reflecte procesele luate in calcul este necesar (1) sa se cunoasca cu acuratete, pe cat posibil, structura genetica si evolutia mediului sedimentar, (2) sa se poata extrapola proprietatile petrografice si hidraulice si, (3) sa se dezvolte instrumente de implementare a acestor proprietati in modele hidrogeologice.

 
 
aprilie 2017
lmmjvsd
12
3456789
10111213141516
17181920212223
24252627282930

SEMINARIO DEL GRUPO DE

HIDROLOGÍA SUBTERRÁNEA

UNIVERSIDAD POLITÉCNICA DE CATALUÑA

"Experimental Upscaling of Flow and Transport in Porous Media"

(autores: A. Englert, N. Güting, T. Vaitl, T. Griese and T. Gökpinar)

a cargo de

Andreas Englert (Ruhr-University Bochum)

 

Día: MIÉRCOLES, 5 de Octubre de 2011

Hora: 12.15 hrs.

Lugar: Aula CIHS (Planta Baja). Departamento Ingeniería del Terreno (módulo D2-UPC).

Andreas Englert (Ruhr-University Bochum)

Día: MIÉRCOLES, 5 de Octubre de 2011

Hora: 12.15 hrs.

Lugar: Aula CIHS (Planta Baja). Departamento Ingeniería del Terreno (módulo D2-UPC).

Abstract:

While the physics of mixing and reaction is well understood at the pore scale, the quantification of these processes at the scales relevant for applications is highly challenging. The inability to sample all the subsurface spatial heterogeneity implies that the processes involved need to be averaged. The loss of information induced by this procedure causes anomalous behaviors of the upscaled dispersion and reaction rates. As mathematical and numerical upscaling of such processes is challenging and such upscaling procedures need to be verified to become useful for proper transport prediction, the project here focuses on experimental laboratory scale upscaling of flow and transport. 
In a first study we examined the potential of laboratory sandbox experiments and studied in detail the impact of the injection near field on the larger scale transport process. Thereto we filled a sandbox with sediments, which were characterized for hydraulic conductivity prior to filling. The latter was then accomplished in such way that different source zone release conditions were arranged by modifying the hydraulic conductivity of injection near-field, while the surrounding hydraulic conductivity field remained unchanged. The experiments in this first sandbox model gave us confidence in laboratory sandbox models and showed that source zone release conditions are of importance for plume development. In detail, we found that source zone release conditions affect the first and second temporal moments, corresponding to the mean arrival time and the spreading of breakthrough curves and the spatial spreading of solute plumes in both the longitudinal and the transverse direction. We further found that in future experiments monitoring of the injection function and subsequent consideration of the measured injection function in the analysis of breakthrough curves might be beneficial for proper parameter estimation. 
In a second study we examined flow and transport in cube shaped sediment samples before and after freezing. Thereto we developed a cube shaped experimental setup, which allows for fill of sediment, performance of flow and transport experiments, freezing of the entire apparatus and withdrawal of a frozen sediment cube from the apparatus. This is an ongoing study. However, first results suggest that the apparatus works and there are only small changes in flow and transport parameters pre- and post- freezing. This is promising for the following experiments. In future studies the frozen sediment cubes will be utilized to arrange heterogeneous sediment formations in sandboxes. Thereto development of an apparatus is ongoing, which will allow to utilize the well explored frozen sediment cubes from experiments in the cube shaped experimental setup. Such experiments will allow experimental upscaling from the dm- to m-scale of the following processes: flow, conservative transport, reactive transport, reactive transport including feedbacks (precipitation and dissolving).

El seminario se podrá ver publicado la próxima semana en la página del grupo: www.h2ogeo.upc.es