VIBROFLOTATION PILING

VIBROFLOTATION HAS THREE BASIC APPLICATIONS: COMPACTION OF GRANULAR SOILS SUCH AS SAND; STRENGTHENING OF COHESIVE SOILS BY THE FORMATION IN THEM OF COMPACTED STONE COLUMNS; IMPROVING THE BEARING CAPACITY OF FILL MATERIALS. TREATMENT OF GRANULAR SOILS IS INTENDED TO MINIMIZE TOTAL AND DIFFERENTIAL SETTLEMENT, AS THERE IS USUALLY NEGLIGIBLE RISK OF SHEAR FAILURE. IN SOFT COHESIVE SOILS THE OBJECTIVE IS TO ELIMINATE SHEAR FAILURE AND, AT THE SAME TIME, TO REDUCE SETTLEMENT. FILL MATERIALS SUCH AS DEMOLITION DEBRIS CAN BE STRENGTHENED TO PRODUCE UNIFORM LOAD-BEARING CHARACTERISTICS. CONVENTIONAL PILES, WHATEVER THE CONSTRUCTION METHOD, HAVE AS THEIR OBJECT THE TRANSFERENCE OF LOAD TO LOWER STRATA OF GOOD BEARING VALUE. VIBROFLOTATION, ON THE OTHER HAND, IS DESIGNED TO STRENGTHEN THE GROUND IMMEDIATELY BELOW THE SURFACE FOOTINGS TO DISPERSE STRESS IN THE STRENGTHENED SOIL. A CONVENTIONAL PILE THUS TAKES ITS DESIGNED LOAD DIRECTLY ON THE PILE WHEREAS VIBROFLOTATION DISTRIBUTES THE LOAD OVER A GIVEN AREA. THERE ARE A NUMBER OF IMPORTANT ECONOMIES IN VIBROFLOTATION COMPARED WITH CONVENTIONAL PILING WHERE BOTH METHODS MAY BE CONSIDERED SUITABLE: (1) HIGH UNIT PRESSURES, THEREFORE SMALL FOOTINGS. (2) FOUNDATION AT SHALLOW DEPTH, THEREFORE NO EXPENSIVE EXCAVATIONS REQUIRED, NOT EVEN BELOW THE GROUNDWATER LEVEL. (3) NORMAL SPREAD FOOTINGS CAN BE CONSTRUCTED ON GROUND TREATED BY VIBROFLOTATION ELIMINATING THE NEED FOR HEAVY REINFORCEMENT AS IN THE CASE OF PILING FOR GROUND BEAMS. (4) IT IS USUALLY CHEAPER THAN PILING SINCE THE DEPTH OF TREATMENT DOES NOT NEED TO BE MUCH GREATER THAN THAT OF THE ELASTIC STRESS BULB. GENERAL CONSIDERATIONS AND SPECIFIC RECOMMENDATIONS ARE DISCUSSED WITH RESPECT TO THE TREATMENT OF FILL AND OF GRANULAR AND COHESIVE SOILS. /AUTHOR/

  • Corporate Authors:

    Cementation Company Ltd /UK

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  • Publication Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 00236250
  • Record Type: Publication
  • Source Agency: Civil Eng & Public Works Review /UK
  • Files: TRIS
  • Created Date: Jan 17 1972 12:00AM