Dynamic analysis of a smooth penetrometer free-falling into uniform clay

The finite-element analysis of free-falling objects penetrating soil deposits is one of the most sophisticated and challenging problems in geomechanics. A robust numerical method will be described here for dealing with such complex and difficult problems. The approach is based on the arbitrary Lagrangian–Eulerian (ALE) method of analysis, the main features and challenges of which are described briefly in the paper. The ALE method is then employed to perform a parametric study of a perfectly smooth penetrometer free-falling into a uniform layer of clay, which deforms under undrained conditions. The effect of the mechanical properties of the clay soil on the penetration characteristics is presented, and an approximate, closed-form expression is derived for the dynamic penetration factor, Ndp. Comparisons are made between the deduced values of Ndp and published values of the conventional cone factor, Nc, and comparisons are made with experimental data to validate the approach.

[1]  J. Lysmer,et al.  Finite Dynamic Model for Infinite Media , 1969 .

[2]  L. John,et al.  Finite dynamic model for infinite media , 1969 .

[3]  R. Scott.  IN-PLACE OCEAN SOIL STRENGTH BY ACCELEROMETER , 1970 .

[4]  John H. Allen,et al.  Instrumented Impact Cone Penetrometer , 1973 .

[5]  Daniel G. True.  Penetration of Projectiles into Seafloor Soils , 1975 .

[6]  Expendable Doppler penetrometer , 1976 .

[7]  J. Graham,et al.  Time effects on the stress-strain behaviour of natural soft clays , 1983 .

[8]  T. Freeman,et al.  A Geotechnical Investigation of a Deep Ocean Site , 1990 .

[9]  Jintai Chung,et al.  A Time Integration Algorithm for Structural Dynamics With Improved Numerical Dissipation: The Generalized-α Method , 1993 .

[11]  M. Randolph,et al.  A practical numerical approach for large deformation problems in soil , 1998 .

[12]  Lindita Kellezi.  Dynamic Soil-Structure-Interaction , 1998 .

[13]  L. Herrmann,et al.  Analysis of steady cone penetration in clay , 2000 .

[14]  C. J. Medeiros.  Low Cost Anchor System for Flexible Risers in Deep Waters , 2002 .

[15]  P. J. Mulhearn.  Influences of Penetrometer Probe Tip Geometry on Bearing Strength Estimates for Mine Burial Prediction , 2002 .

[16]  Roman D. Hryciw,et al.  Large displacement FEM modelling of the cone penetration test (CPT) in normally consolidated sand , 2003 .

[17]  M. Randolph,et al.  Experimental and theoretical studies of deep penetrating anchors , 2004 .

[18]  D. Sheng,et al.  Stress integration and mesh refinement for large deformation in geomechanics , 2006 .

[19]  Charles Aubeny,et al.  Interpretation of Impact Penetration Measurements in Soft Clays , 2006 .

[20]  I. E. Ina,et al.  Effect of strain rate on mobilised strength and thickness of curved shear bands , 2006 .

[21]  Majidreza Nazem,et al.  Arbitrary Lagrangian–Eulerian method for large‐strain consolidation problems , 2008 .

[22]  High penetration rate CPT to determine damping parameters for rapid load pile testing , 2008 .

[23]  Lidija Zdravković,et al.  An assessment of time integration schemes for dynamic geotechnical problems , 2008 .

[24]  Mark Randolph,et al.  Large deformation finite element analysis for offshore applications , 2008 .

[25]  Majidreza Nazem,et al.  Some computational aspects for solving deep penetration problems in geomechanics , 2009 .

[26]  Julian Simeonov,et al.  Numerical investigation of dynamic free-fall penetrometers in soft cohesive marine sediments using a finite element approach , 2009, OCEANS 2009.

[27]  Majidreza Nazem,et al.  Arbitrary Lagrangian–Eulerian method for dynamic analysis of geotechnical problems , 2009 .

[28]  S. Liyanapathirana.  Arbitrary Lagrangian Eulerian based finite element analysis of cone penetration in soft clay , 2009 .

[29]  Majidreza Nazem,et al.  Alternative stress-integration schemes for large-deformation problems of solid mechanics | NOVA. The University of Newcastle's Digital Repository , 2009 .

[30]  Zvi Rosenberg,et al.  The penetration of rigid long rods – revisited , 2009 .

[31]  Andrei Abelev,et al.  Numerical investigation of dynamic free-fall penetrometers in soft cohesive marine sediments using a finite difference approach , 2009, OCEANS 2009.

[32]  Mark Randolph,et al.  Rate effects on penetrometer resistance in kaolin , 2009 .

[33]  Majidreza Nazem,et al.  Dynamic analysis of free-falling penetrometers in soil deposits , 2010 .

[34]  Rate effects in free falling penetrometer tests , 2011 .

[35]  P. Wriggers.  Computational contact mechanics , 2012 .