An approach to evaluation of field CPTU dissipation data in overconsolidated fine-grained soils

Dissipation of excess pore pressures during piezocone testing in firm to stiff overconsolidated fine-grained soils provides data curves that cannot be interpreted using published theoretical solutions. Available solutions are based on either cavity-expansion or strain-path methods, which have been developed for soft, normally consolidated soils and do not adequately model the response in overconsolidated soils. During penetration in overconsolidated soils, large pore-pressure gradients and unloading can exist as the soil moves past the singularity at the cone tip shoulder; these gradients modify the initial pore-pressure distribution around the tip and along the friction sleeve and give rise to nonstandard dissipation curves. The different types of response resulting from the modified pore-pressure distribution are discussed and classified and a correction technique is proposed. In this way, the application of available theoretical models can be used to evaluate in situ flow characteristics. Examples of the different types of pore-pressure response are presented from various sites worldwide.

[1]  Discussion of “ Consolidation After Undrained Piezocone Penetration. I: Prediction ” by Mohsen M. Baligh and Jacques‐Noel Levadoux (July 1986) , 1988 .

[2]  C. P. Wroth,et al.  Field studies of an instrumented model pile in clay , 1989 .

[3]  Alan J. Lutenegger,et al.  IN SITU ESTIMATION OF THE COEFFICIENT OF CONSOLIDATION IN CLAYS , 1990 .

[4]  M. Uslenghi,et al.  The World Space Observatory (WSO-UV) - Current status , 2008, 0801.2080.

[5]  J. P. Sully,et al.  Estimating coefficient of consolidation from piezocone tests , 1992 .

[6]  Cee-Ing Teh,et al.  An analytical study of the cone penetration test , 1991 .

[7]  Jacques-Noel Levadoux,et al.  Pore pressures in clays due to cone penetration , 1980 .

[8]  Jjm Powell,et al.  INTERPRETATION AND USE OF THE PIEZOCONE TEST IN UK CLAYS. PENETRATION TESTING IN THE UK. PROCEEDINGS OF THE GEOTECHNOLOGY CONFERENCE ORGANIZED BY THE INSTITUTION OF CIVIL ENGINEERS AND HELD IN BIRMINGHAM ON 6-8 JULY 1988 , 1989 .

[9]  Richard J. Jardine,et al.  Effects of installing displacement piles in a high OCR clay , 1991 .

[10]  R G Campanella,et al.  INTERPRETATION OF PIEZOCONE SOUNDINGS IN CLAY - A CASE HISTORY. PENETRATION TESTING IN THE UK. PROCEEDINGS OF THE GEOTECHNOLOGY CONFERENCE ORGANIZED BY THE INSTITUTION OF CIVIL ENGINEERS AND HELD IN BIRMINGHAM ON 6-8 JULY 1988 , 1989 .

[11]  Derek Elsworth,et al.  Analysis of piezocone dissipation data using dislocation methods , 1993 .

[12]  R. G. Campanella,et al.  Current status of the piezocone test , 1988 .

[13]  Mohsen M. Baligh,et al.  Consolidation After Undrained Piezocone Penetration II: Interpretation , 1986 .

[14]  M. M. Baligh,et al.  CONSOLIDATION AFTER UNDRAINED PIEZOCONE PENETRATION. I: PREDICTION , 1986 .

[15]  Peter K. Robertson,et al.  Use of Piezometer Cone Data , 1986 .

[16]  Mehmet Y. Tumay,et al.  Subsurface Investigations with Piezo-Cone Penetrometer , 1981 .

[17]  J P Sully,et al.  Closure of "Overconsolidation Ratio of Clays from Penetration Pore Pressures" , 1990 .

[18]  C I Teh,et al.  ANALYSIS OF THE CONE PENETRATION TEST BY THE STRAIN PATH METHOD. PROCEEDINGS OF THE SIXTH INTERNATIONAL CONFERENCE ON NUMERICAL METHODS IN GEOMECHANICS, 11-15 APRIL 1988, INNSBRUCK, AUSTRIA. VOLUMES 1 - 3 , 2017 .