INVESTIGATIONS CONCERNING A DEEP COFFERDAM IN THE THAMES ESTUARY CLAY AT SHELLHAVEN

DURING THE CONSTRUCTION OF A DEEP COFFERDAM FOR A PUMP- HOUSE IN THE THAMES ESTUARY CLAY AT SHELLHAVEN, A DETAILED SITE INVESTIGATION WAS CONDUCTED, COUPLED WITH LABORATORY TESTS, AND REASONABLY COMPLETE DATA WERE OBTAINED CONCERNING THE SOIL PROPERTIES. THE INVESTIGATION WAS CONDUCTED WITH IN SITU VANE TESTS AND BY LABORATORY TESTS ON UNDISTURBED SAMPLES, SOME TAKEN FROM A BOREHOLE AND OTHERS TAKEN DURING THE EXCAVATION OF A SHAFT IMMEDIATELY ADJACENT TO THE COFFERDAM. THE STRATA CONSISTS OF SOFT POST-GLACIAL CLAY, WITH LAYERS OF PEAT AND SILT TO A DEPTH OF ABOUT 46 FEET, BELOW WHICH THERE IS A LAYER ABOUT 6 FEET THICK OF FIRM SANDY CLAY, FOLLOWED BY A CONSIDERABLE DEPTH OF SANDY GRAVEL. COFFERDAM EXCAVATION INSIDE EXTENDED TO A DEPTH OF 32 FEET BELOW GROUND LEVEL. HEAVY STEEL SHEET-PILING WAS DRIVEN TO A DEPTH OF 65 FEET TO FORM THE OUTER WALLS OF THE COFFERDAM AND THREE BOLTED STEEL-FRAMES OF WALINGS AND STRUTS WERE ERECTED TO SUPPORT THE STEEL PILINGS AS EXCAVATION PROCEEDED. DURING CONSTRUCTION, OBSERVATIONS WERE MADE ON THE LOADS TRANSMITTED TO THE WALINGS AND ON THE STRAINS IN THE STRUTS, IN ONE SECTION OF THE COFFERDAM. THE LOADS TRANSMITTED FROM THE SHEET-PILING WALLS TO THE WALINGS, AND THE LOADS IN THE STRUTS WERE MEASURED. ALL TEST RESULTS ARE REPORTED AND RESULTS ARE INTERPRETED BY MEANS OF EARTH PRESSURE CALCULATIONS. IT IS CONCLUDED THAT THE OBSERVED LOADS IN THE BRACING OF THE COFFERDAM CAN BE ACCOUNTED FOR IN TERMS OF DEFLECTIONS OF THE SHEET PILING PRIOR TO PLACING THE STRUTS IN POSITION, AND WITHOUT THE NEED FOR ASSUMING A REDISTRIBUTION OF EARTH PRESSURE.

  • Availability:
  • Supplemental Notes:
    • Vol 3, No 3, PP 119-139, 11 FIG, 4 TAB, 1 PHOT, 13 REF
  • Authors:
    • SKEMPTON, A W
    • Ward, W H
  • Publication Date: 1952-9

Media Info

  • Serial:
    • GEOTECHNIQUE
    • Publisher: Thomas Telford Limited
    • ISSN: 0016-8505

Subject/Index Terms

Filing Info

  • Accession Number: 00234430
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Aug 28 1994 12:00AM