Nondestructive Sample Quality Assessment of a Soft Clay Using Shear Wave Velocity

Landon, Melissa M.; DeGroot, Don J.; Sheahan, Thomas C.

doi:10.1061/(asce)1090-0241(2007)133:4(424)

Cited by 73 publications

(24 citation statements)

References 14 publications

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“…Two tube samples (from S2 and S4) appear below the reconstituted sample, which is indicative of their poor quality, thus enabling to confirm the proposed limits of this classification. There is some parallelism between this new classification and that proposed by [38] based upon tests on Boston blue clay and [68] for Bothkennar soft clay. In their research, these authors compared laboratory and in situ shear wave velocities and used the reconsolidation strains method by Lunne et al [43] to define the categories of sample quality.…”

Section: Assessment Of Sampling Quality By Comparison Of Seismic Wavementioning

confidence: 75%

“…Arroyo et al [3] observed that the normalized shear wave measurements showed a better correlation with sample quality when taken after recompression than when taken after re-saturation. Values reported by Landon et al [38] for Boston Blue Clay show a clear ordering of V s with sample quality, with the Sherbrooke rating above the piston tubes, those above the Shelby and STP. V s reduced to 0.35V s-(SDMT) and 0.15 V s-(SDMT) in specimens retrieved with Shelby tube and SPT sampler, respectively.…”

Section: Shear Wave Velocity Measurementsmentioning

confidence: 75%

“…b Silty deposits from Castelló d'Empuries [3] sampling. Values of shear wave velocity measured at unconfined conditions (e.g., [15,38]) as well as at in situ stress conditions (e.g., [68,69]) are the two procedures followed in laboratory to assess sample quality using wave propagation techniques. Both have shown good correlation with sample quality descriptors e v and De/e 0 for a wide variety of soils.…”

Section: Shear Wave Velocity Measurementsmentioning

confidence: 99%

“…Both have shown good correlation with sample quality descriptors e v and De/e 0 for a wide variety of soils. Figure 36 shows V s estimates for three natural soils: low-plasticity Boston Blue clay (USA) [38], low-plasticity silty deposits from Castelló d'Empuries [3] as well as high-plasticity Ballina clay [58]. Block (Sherbrooke) specimens as well as tube samples (fixed piston, Shelby tube, and SPT samplers) are included in this figure.…”

Section: Shear Wave Velocity Measurementsmentioning

confidence: 99%

“…It is very important to be able to assess the quality of the samples, to guarantee that only high-quality samples are used for extensive laboratory characterization. Different methods for the assessment of sampling quality have been proposed over the years relying on: fabric inspection; measurement of initial mean effective stress, p 0 [37]; measurement of strains during reconsolidation [43]; and comparison of in situ and laboratory measurements of seismic wave velocities [21,38,49,64,68]. It is worth highlighting that among the commonly used methods for assessing sample quality, the last is the only one capable of effectively considering the effects of destructuration in soils with low reconsolidation strains and conditions ahead of the advancing borehole during drilling operations; penetration of the sampling tube and sample retrieval to ground surface; water content redistribution in the tube; extrusion of the sample from the tube; drying and/or changes in water pressures; stress relief due to the removal of the sample from the ground to zero total stress state in the laboratory; and trimming and other processes required to prepare specimens for laboratory testing [80].…”

Section: Introductionmentioning

confidence: 99%

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Getting high-quality samples in ‘sensitive’ soils for advanced laboratory tests

Fonseca

Pineda

2017

Innov. Infrastruct. Solut.

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Laboratory tests are well recognized as highly appropriate for defining the engineering properties of geomaterials, in terms of constitutive law parameters for modeling geotechnical engineering problems. The strong development of advanced techniques, both in equipment and in data interpretation, has increased the confidence in laboratory testing, while on the other hand the limitations due to the quality of soil sampling with depth and the spatial representativeness of the samples are less consensual. Still, the development of new methods for assuring high-quality samples is increasing, together with sampling quality assessment by non-destructive methods using vibration wave velocities. Interpretation methods of in situ tests for ground characterization have also evolved significantly, increasing the reliability of these methods. Their versatility to cover large areas on site and the fact that these tests are, in principle, performed at the actual state (physical and stress) conditions, as well as the improvements in the correlations between field tests and hydraulic and geomechanical parameters, allow joining the quality of data and theoretical approaches, namely through critical state soil mechanics. This keynote paper discusses some of the aspects that can and should enable the association of ground characterization from laboratory testing over undisturbed samples used in more or less advanced tests, enhancing the determinant conditioning factor, that is, the sampling technique to get representative specimens and the way this is assessed. The confidence that we expect to have on the geomechanical parameters that we need for our geotechnical activities will mostly depend on this in view of the high uncertainties of the parametrical correlations with in situ test data, therefore, important in ground characterization. This is especially relevant in sensitive soils, such as soft fine soils, loose sandy soils, or young residuals soils. These have or can have ''weak'' equilibria of the interparticle micro-and macrostructures (or their arrangement, fabric) that will change substantially their properties if samples are collected and conditioned with processes that do not preserve that intrinsic ''ADN''. The change in these natural conditions can be evaluated by techniques of quality assessment, which will be discussed in what follows.

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Section: Assessment Of Sampling Quality By Comparison Of Seismic Wavementioning

confidence: 75%

Section: Shear Wave Velocity Measurementsmentioning

confidence: 75%