A LABORATORY STUDY OF THE EFFECTS OF REPEATED LOADING ON THE CONSOLIDATION OF A SUBGRADE MATERIAL

This project reports on an investigation of the effects of stress, consolidation ratio, dry density and frequency of a saturated artificial sand, silt, clay mixture to repeated loading. In particular, the response of the material to repeated axial compressive stress was studied using a pneumatically-driven repeated load oedometer cell. The specimens tested were compacted using floating mould compaction to three density levels (2.0,2.06 and 2.12g/cm3). Two consolidation ratios were examined, namely unconsolidated and over-consolidated. Frequencies of testing included 20 and 40 cycles per minute. The vertical stress varied from 34.5 to 379.1 kpa, whilst the samples were laterally confined in an oedometer ring. Each specimen was subjected to the repeated stress for 24 hours, with a cycle time ranging from 1.5 to 3.0 seconds, depending on the frequency used. Material behaviour was expressed in terms of peak, resilient and plastic components of deformation for varying consolidation ratios, frequencies and dry densities. The literature suggested that there may be a critical dry density at which the resilient strains of repetitively stressed soils are minimum. This was confirmed in this investigation. Further, that as stress levels increased resilient deformation was found to decrease. Overconsolidated specimens exhibited lower peak, plastic and resilient axial strains than unconsolidated specimens. It was also found that deformation was independent of frequency of loading but was dependent on the number and magnitude of stress applications. /TRRL/

• Corporate Authors:

  University of New South Wales

  School of Highway Engineering
  Kensington, New South Wales  Australia  2033
• Authors:
  • GRANT, R
• Publication Date: 1976

Language

• English

Media Info

• Features: Figures; Photos; References; Tables;
• Pagination: 122 p.

Subject/Index Terms

• TRT Terms: Accelerated tests; Clay; Compaction; Compression; Consolidation; Consolidations; Deformation; Density; Frequency (Electromagnetism); Laboratories; Laboratory studies; Oedometers; Overconsolidation; Percent saturation; Repeated loads; Resilience (Materials); Sand; Silts; Strain (Mechanics); Stresses; Subgrade (Pavements)
• Uncontrolled Terms: Axial strain; Vertical stress
• Old TRIS Terms: Consolidation ratio
• ITRD Terms: 5532: Compression; 5791: Consolidation (soil); 5595: Deformation; 5907: Degree of saturation (mater); 5908: Density; 6997: Frequency; 6237: Laboratory (not an organization); 6168: Oedometer; 5588: Repetitive loading; 4105: Sand; 4149: Silt; 5575: Stress (in material); 2950: Subgrade
• Subject Areas: Geotechnology; Highways;

Filing Info

• Accession Number: 00164154
• Record Type: Publication
• Source Agency: Transport and Road Research Laboratory (TRRL)
• Report/Paper Numbers: Monograph
• Files: ITRD, TRIS
• Created Date: Jun 28 1978 12:00AM