FULL SCALE FIELD TESTS WITH A SLURRY TRENCH EXCAVATION IN SOFT CLAY

A TEST SLURRY TRENCH, 1 M WIDE, 5 M LONG AND 28 M DEEP WAS EXCAVATED IN SOFT CLAY AND WAS INSTRUMENTED TO PERMIT MEASUREMENT OF SETTLEMENTS AND LATERAL DEFORMATIONS OF THE SURROUNDING GROUND AS WELL AS PORE PRESSURES. A SLURRY WITH A DENSITY OF 1.24 T/CU M WAS USED DURING EXCAVATION. THE TRENCH WAS OBSERVED FOR 31 DAYS, DURING WHICH TIME THE DENSITY OF THE SLURRY WAS REDUCED IN TWO STAGES FROM 1.24 TO 1.10 T/CU M AND FROM 1.10 TO 1.00 T/CU M. AT THE END OF THE PROGRAM THE TEST PANEL WAS CONCRETED. THE OVERALL STABILITY OF THE TRENCH AGAINST FAILURE WAS SUFFICIENT THROUGHOUT THE TEST PROGRAM. DURING EXCAVATION THE MAXIMUM MEASURED SETTLEMENT WAS 5 MM, WHICH OCCURRED AT THE GUIDE WALL; AT THE END OF THE TEST PROGRAM THE MAXIMUM SETTLEMENT, AGAIN AT THE GUIDE WALL, WAS ONLY 8 MM. EVEN THOUGH THE SLURRY-FILLED TRENCH WAS KEPT OPEN FOR 31 DAYS, THE MAXIMUM INWARD CREEP OF THE WALLS DECREASED THE WIDTH OF THE TRENCH BY ONLY 5.5 CM. THE OBSERVED SETTLEMENTS AND THE MEASURED CHANGES IN THE WIDTH OF THE TRENCH INDICATE THAT THE CREEP OF THE SURROUNDING SOIL WAS ALMOST THE SAME WHEN THE DENSITY OF THE SLURRY WAS 1.24 T/CU M AND 1.10 T/CM. WITH WATER IN THE TRENCH, MOVEMENTS OF THE SOIL OCCURRED AT A SLIGHTLY FASTER RATE BUT THEY NEVER TENDED TO ACCELERATE WITH TIME. /AUTHOR/

  • Authors:
    • DiBiagio, E
    • Myrvoll, F
  • Publication Date: 1972

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  • Accession Number: 00236407
  • Record Type: Publication
  • Files: TRIS
  • Created Date: May 29 1973 12:00AM