THE LOWERING OF THE WATER TABLE APPLIED TO THE DRYING AND THE EXTRACTION OF HIGHWAY MATERIALS

LE RABATTEMENT DE NAPPE APPLIQUE A L'ASSECHEMENT ET A L'EXTRACTION DE MATERIAUX ROUTIERS.

IN THE SAONE VALLEY, THE TECHNIQUE OF WATER TABLE DRAWDOWN APPLIED TO THE DRYING AND THE EXTRACTION OF MATERIAL WAS USED FOR THE FIRST TIME ON A LARGE SCALE DURING THE CONSTRUCTION OF THE A6 MOTORWAY. THE ADVANTAGES AND THE SIMPLICITY OF THIS METHOD HAVE MADE IT A CLASSICAL SOLUTION; NOWADAYS IT IS USED VERY FREQUENTLY. FOLLOWING AN EXAMINATION OF THE ADVANTAGES AND THE DISADVANTAGES OF THE TECHNIQUE, THE ARTICLE, BASED ON OBSERVATIONS IN SEVERAL DEPOSITS, ATTEMPTS TO DEFINE WHY AND HOW SUCH A METHOD IS CHOSEN; HOW THE PUMPING IS CARRIED OUT; HOW THE MATERIAL IS DRIED. THE ARTICLE OUTLINES THE DIFFICULTIES WHICH WERE ENCOUNTERED IN THE PREDICTION OF THE SPEED OF DRYING AND THE FINAL WATER CONTENT OF THE AGGREGATE; THE CONSEQUENCES OF PUMPING ON THE WATER TABLE, THE PROBLEMS OF EMPTYING AND RECHARGING OF THE GROUNDWATER. FINALLY, A COMPARISON IS MADE BETWEEN THE PREDICTIONS AND REAL CONDITIONS: THE CALCULATED DISCHARGE PREDICTED IS SUFFICIENTLY CLOSE TO THAT ACTUALLY MEASURED, BUT THE PRECISION OF THE STUDIES REMAINS FAIRLY LOW; THIS IS NOT, HOWEVER, VERY IMPORTANT IN THE FIELD OF INDUSTRIAL EXTRACTION; THE ORDER OF MAGNITUDE IS ALL THAT IS NECESSARY. THE ARTICLE CONCLUDES BY STRESSING: ON THE ONE HAND THE NECESSITY TO TAKE CERTAIN PRECAUTIONS; THE LACK OF KNOWLEDGE OF THE LAWS GOVERNING THE DRYING OF A MATERIAL AND THE DIFFICULTIES INVOLVED IN MAKING A REASONABLE ESTIMATE. TAKING ACCOUNT OF ACTUAL NEEDS, THIS METHOD MUST BE DEVELOPED FURTHER, PARTICULARLY IN THE EXTRACTION OF CLAY MATERIALS.

Language

  • French

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Filing Info

  • Accession Number: 01296712
  • Record Type: Publication
  • Source Agency: Institut Francais des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)
  • Files: ITRD
  • Created Date: Nov 21 2010 6:02AM