G max-qc Relationships for Clays

Abstract

Data are compiled from 31 clay sites where in-situ measurements of initial tangent shear modulus (Gmax) and cone tip resistance (qc) were available. Values of Gmax were obtained from either seismic cone penetration (SCPT), crosshole (CHT), downhole (DHT), or spectral analysis of surface wave (SASW) tests, and readings of qc were taken either by regular cone penetration (CPT) or piezocone (CPTU) tests. Multiple regression analyses indicate that in-situ values of Gmax depend on void ratio (eo), overburden stress (σ′vo), and stress history (OCR), as previously established from laboratory resonant column tests. Since qc also depends on σ′vo and OCR, a moderate association between Gmax and qc is possible, despite their incompatible strain levels. For preliminary correlative purposes, a power function relates in-situ Gmax, qc, and eo in clay deposits having a wide range in plasticity, sensitivity, stress history, and consistency.

Simplified Constitutive Model for Simulation of Cyclic Response of Shallow Foundations: Validation against Laboratory Tests

“…3(c)]. It can be directly computed on the basis of the measured shear wave velocity V s , or estimated from empirical correlations (e.g., Hardin and Richart 1963;Robertson and Campanella 1983a, b;Seed et al 1986;Mayne and Rix 1993) and expressed as a function of the overburden stress σ y :…”

A Critical Review of CPT-based Correlations for Shear Wave Velocity in North Sea Soils

“…However, for measurements with G max > 300MPa, an underestimation was still noticed. Mayne and Rix [9] determined a relationship between small-strain shear modulus and cone tip resistance by studying 481 data points from 31 sites all over the world. The database contains a wide range of clay materials, ranging from soft organic clay to overconsolidated, fissured clay.…”

“…G max ranged between about 0.7 MPa and 800 MPa. From the vertical effective stress data presented by the authors [9], a maximum test depth of approximately 30m is identified. Based on the available data, the authors proposed a simple formula which only depends on cone tip resistance.…”

“…When direct shear wave velocity measurements at the location under consideration are not available, a correlation between conventional CPT measurements and shear wave velocity (or small-strain stiffness) is generally used. Several authors have formulated correlations between CPT measurements and G max or V s [8][9][10][11][12][13][14][15][16], each based on a dataset containing both CPT measurements and direct measurement of V s . It should be noted that G max and V s are related through the fundamental relation G max = ρV 2 s , where ρ is the bulk density of the soil.…”

A microelectromechanical system digital 3C array seismic cone penetrometer

“…Field-observed correlations in SCPT between q c and V S are used by many authors (e.g., Baldi et al, 1989;Mayne and Rix, 1993;Hegazy and Mayne, 1995;Eslaamizaad and Robertson, 1998;Simonini andCola, 2000, Andrus et al, 2004;Schneider et al, 2004, among others). The V S changes from SCPT are linked with the reflections seen in surface shear wave data to extend 1D information of soil stratigraphy to 2D or 3D (Ghose et al, 1996Brouwer et al, 1997;Jarvis and Knight, 2000;Ghose and Goudswaard, 2004;Knight and Pidlisecky, 2005).…”