Nunziante Squeglia, Lo Presti Diego, Barbara Cosanti
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Transcript of Nunziante Squeglia, Lo Presti Diego, Barbara Cosanti
Nunziante Squeglia, Lo Presti Diego, Barbara Cosanti
UNIVERSITA’ DI PISADipartimento di Ingegneria dell’Energia, dei Sistemi del Territorio e delle Costruzioni
Re – evaluation of classification charts for CPTU in partially saturated loose silt mixtures
WORKSHOP ON PENETRATION TESTING 9 OCTOBER 2014
AUDITIORIUM OPERA PRIMAZIALE
MOTIVATIONS
SBT CLASSIFICATION CHARTS DO NOT CORRECTLY WORK IN CASE OF:
– PARTIALLY SATURATED SOILS
– LOOSE SILT MIXTURES
PARTIALLY SATURATED SOILS
EXAMPLE
BRONI (PV) SITE
Fine grained soil
POSSIBLE CORRECTION
EVALUATE SUCTION and CORRECT EFFECTIVE STRESS
ADOPTED MODEL
MK – KOVACS (Aubertin et al., 2003)
– granular soil f(D10, CU)
– fine soil f(LL)
EFFECT OF CORRECTION (Ic): - BRONI
ROBERTSON & CAMPANELLA (1986)ROBERTSON (1990)
EFFECT OF CORRECTION (SBT): BRONI
EFFECT OF CORRECTION (SBT): BRONI
LOOSE SILTY MIXTURES: Qc < 1 MPa
SERCHIO RIVER EMBANKMENTS
Ic FROM BOREHOLES VS. Ic FROM CPTU
Ic FROM BOREHOLES & CPTU
EFFECT OF CORRECTION
EFFECT OF CORRECTION
HOW TO DISTINGUISH LOOSE SILT MIXTURES FROM COMPRESSIBLE CLAYS ETC.
• COMPRESSIBLE CLAYS, PEATS, ETC. CAN HAVE qc < 1 MPa
• MAY FR GIVE USEFUL INDICATIONS?
• FRICTION RATIO < 4?
COMPRESSIBLE CLAYS: PISA EST
COMPRESSIBLE CLAYS: PISA WEST
COMPRESSIBLE CLAYS: PISA DISTRICT
COMPRESSIBLE CLAYS: LIVORNO DISTRICT
COMPRESSIBLE CLAYS: LUCCA DISTRICT
COMPRESSIBLE CLAYS: PRATO DISTRICT
EFFECT OF SLEEVE DIAMETER (HOSKIN ET AL., 2014)(NZ - SANDS)
ACKNOWLEDGEMENTS
• CPT DATA IN TUSCANY HAVE BEEN PROVIDED BY GEOSERVIZI (COSCO & SPADARO)
• CPT INTERPRETATION HAS BEEN CARRIED OUT BY SCARDIGLI & ZACCAGNINO (UNDERGRADUATER STUDENTS)
• CPT DATA FROM BRONI HAVE BEEN GIVEN BY PAGANI AND DR. MEISINA (UNIPV)
• CPT INTERPRETATION OF BRONI DATA HAS BEEN CARRIED OUT BY ROSIGNOLI (GRADUATE STUDENT)