STANDARD PENETRATION TEST AND FOUNDATION PRACTICE IN FINE SANDS IN ISRAEL

THE CONVENTIONAL FOUNDATION PRACTICE FOR MEDIUM SIZE BUILDINGS ON FINE SANDS, USUALLY DUNE SANDS IN ISRAEL, IS DESCRIBED. THE PROPERTIES OF THESE SANDS HAVE BEEN INVESTIGATED AND EXTENSIVE STANDARD PENETRATION TEST (SPT) DATA HAVE BEEN ACCUMULATED. THE SPT VALUES OF NATURAL DEPOSITS ARE LOW. A FIELD INVESTIGATION SHOWED THAT THE CORRECTION FOR DEPTH EFFECT PROPOSED BY THE US BUREAU OF RECLAMATION (U.S.B.R.) IS APPROPRIATE AND NECESSARY FOR UNDERSTANDING THE PERFORMANCE OF BUILDINGS IN THESE SANDS. THE NEED FOR CONFIRMATION OF EMPIRICAL DESIGN RECOMMENDATIONS IN THE LIGHT OF THE LOCAL ENGINEERING PRECEDENT AND TEST METHODS IS DEMONSTRATED. CONSIDERATION IS GIVEN TO THE COMPLICATION INTRODUCED BY THE STRESS HISTORY IN INTERPRETING THE RESULTS. THE IMPEDANCE OF THE FREE FALL OF THE DRIVE WEIGHT OF THE SPT IS SHOWN TO INFLATE THE BLOW COUNT VALUE (N). THE RELATIVE DENSITY ESTIMATED BY APPLYING THE U.S.B.R. RECOMMENDATIONS TO SUCH INFLATED N VALUES MAY BE TOO HIGH BY 20 POINTS.