00231356

Component

http://onlinepubs.trb.org...rbbulletin/325/325-004.pdf

THE COMPACTION OF SAND WAS INVESTIGATED WITH ALMOST WEIGHTLESS TAMPERS HAVING SEVERAL BASE PLATE DIMENSIONS AND OPERATED MECHANICALLY AT THE SURFACE OF DRY SAND AT VARYING FREQUENCIES INCLUDING THE SUPERSONIC RANGE. SOME EVALUATION WAS MADE OF THE MAXIMUM POSSIBLE LABORATORY SAND DENSITY. RESULTS OBTAINED INDICATE THAT 25 CPS IS THE MOST EFFICIENT VIBRATION FREQUENCY FOR COMPACTING THE DRY SAND USED IN THE INVESTIGATION OVER THE TAMPER-SIZE RANGE USED. THE EFFICIENCY OF HIGHER & LOWER FREQUENCIES DROPS SHARPLY FROM THIS OPTIMUM INDICATING THAT VIBRATION SHOULD NOT BE APPLIED AT RANDOM FREQUENCIES, BUT CLOSELY CONTROLLED FOR BEST RESULTS. EVEN AT OPTIMUM FREQUENCY THE VIBRATIONS MUST BE APPLIED FOR AN APPRECIABLE LENGTH OF TIME TO OBTAIN REASONABLE DENSITIES. MAXIMUM COMPACTION IS NOT ATTAINED IMMEDIATELY BELOW THE TAMPER BUT AT SOME DISTANCE BELOW THE VIBRATING PLATE. THE RATIO OF THIS DISTANCE TO THE PLATE WIDTH DECREASED AS THE PLATE WIDTH BECAME LARGER BUT NOT IN A STRAIGHT LINE VARIATION. THERE IS SOME EVIDENCE THAT THIS RATIO VARIED WITH THE TAMPING FORCE BECAUSE THE TAMPING FORCE ALSO DECREASED AS THE PLATE SIZE INCREASED. IT IS CONCLUDED THAT COMPACTION OF DRY SAND BY VIBRATION IS CONTROLLED BY THE FREQUENCY OF VIBRATION AND IS GREATEST AT THE CRITICAL FREQUENCY. THE CRITICAL FREQUENCY IS THE ONE THAT GIVES THE GREATEST SETTLEMENT OF SURCHARGE LOAD. NO COMPACTION WAS OBTAINED AT SUPERSONIC FREQUENCIES. AN EQUATION IS PRESENTED THAT GIVES THE DEGREE OF COMPACTION AS A FUNCTION OF TIME. SURCHARGE IS EFFECTIVE IN TRANSMITTING THE MAXIMUM COMPACTION TO LOWER DEPTHS. THE MAXIMUM DEPTH AND MAXIMUM WIDTH TO WHICH COMPACTION IS EFFECTIVE IS AN EXPONENTIAL FUNCTION OF TAMPER DIMENSIONS.

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01410706

English

pp 44-54

1962

Highway Research Board Bulletin

41st Annual Meeting of the Highway Research Board

Print

Figures (23) ; References (30)

Beach sands; Compaction; Depth; Equations; Soil compaction; Soil stabilization; Tamping; Time; Vibratory compaction; Width

Surcharge

Geotechnology; Highways

TRIS, TRB, ATRI

Aug 15 2004 2:41AM

• COMPACTION CHARACTERISTICS OF SOME BASE AND SUBBASE MATERIALS
• CORRELATION OF COMPACTION AND CLASSIFICATION TEST DATA
• SUGGESTED COMPACTION STANDARDS FOR CRUSHED AGGREGATE MATERIALS BASED ON EXPERIMENTAL FIELD ROLLING