Engineering Geology of Soft Clay

Brenner, Robert; Nutalaya, Prinya; Chilingarian, George V.; Robertson, John O.

doi:10.1016/b978-0-444-41784-8.50005-8

Cited by 14 publications

(14 citation statements)

References 81 publications

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“…As a result, they may have become highly sensitive or ‐quick‐ if sufficient leaching of salt from the soil pore water occurred. Although leaching does not usually affect the flocculated structure, it can, however, strongly affect the interparticle forces, reducing the capacity of the particles to reflocculate following remoulding (Brenner et al ). Remoulding of these materials will therefore result in a low viscosity liquid containing small and separated particles.…”

Section: Introductionmentioning

confidence: 99%

Multi‐method geophysical mapping of quick clay

Donohue

Long

O’Connor³

et al. 2012

Near Surface Geophysics

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The UCD community has made this article openly available. Please share how this access benefits you. Your story matters! (@ucd_oa) Some rights reserved. For more information, please see the item record link above. ABSTRACT Marine clay deposits in coastal, post-submarine areas of Scandinavia and North America may be subjected to quick clay landslides and hence significant efforts are being taken to map their occurrence and extent. The purpose of this paper is to assess the use of a number of geophysical techniques for identifying quick clay. The investigated area, Smørgrav, located in southern Norway has a history of quick clay sliding, the most recent event occurring in 1984. Geophysical techniques that are used include electromagnetic conductivity mapping, electrical resistivity tomography, seismic refraction and multichannel analysis of surface waves. These results are compared to geotechnical data from bore samples, rotary pressure soundings and cone penetration testing. A number of these approaches have proved promising for identifying quick clay, in particular electrical resistivity tomography and electromagnetics, which delineated a zone of quick clay that had previously been confirmed by rotary pressure soundings and sampling. Seismic refraction was useful for determining the sediment distribution as well as for indicating the presence of shallow bedrock whereas the multichannel analysis of surface-waves approach suggested differences between the intact stiffness of quick and unleached clay. It is observed that quick clay investigations using discrete rotary pressure soundings can be significantly enhanced by using, in particular, electrical resistivity tomography profiles to link together the information between test locations, perhaps significantly reducing the need for large numbers of soundings.

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Section: Introductionmentioning

confidence: 99%

Multi‐method geophysical mapping of quick clay

Donohue

Long

O’Connor³

et al. 2012

Near Surface Geophysics

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“…The salinity was determined from the measurement of electrical conductivity on the pore water that was extracted from dried soil sample by using distilled water. The relationship reflects the fact that even for the same material components the higher flocculent structure has a larger increase of salinity, as in a study of Brenner et al (1981). Plasticity of the clays is shown in Figure 11.…”

Section: Correlation Of Soil Propertiesmentioning

confidence: 88%

Geological and Geotechnical Characteristics of Marine Clays at the Busan New Port

Chung

Ryu

et al. 2005

Marine Georesources & Geotechnology

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“…The geochemistry of the porewater is extremely important for the development of quick clay. This was observed in the 1920s (Holmsen 1929) and has been investigated in a great number of studies since then (e.g., Bjerrum 1954;Söderblom 1969;Torrance 1975 and a summary by Brenner et al 1981). Originally depos-tion E23/910.…”

Section: Formation Of Quick Claymentioning

confidence: 94%

Mapping of quick clay using geoelectrical imaging and CPTU‐resistivity

Dahlin

Löfroth

Schälin

et al. 2012

Near Surface Geophysics

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Quick clay has a major impact on landslide risk and it is therefore of considerable interest to map its presence and extent. In Sweden, quick clay has been involved in most landslides in soft clay with serious consequences. The predominant method for detection of quick clay in Sweden has been to take undisturbed samples and to perform fall‐cone tests on the clay in its undisturbed and remoulded state. Originally deposited in saltwater in a marine environment, the salt maintains the stability of the clay. When the salt is leached out, the clay can become quick. When salt is leached from clay of marine origin the resistivity increases. In this study the intention was to calibrate electrical imaging with cone penetration tests with resistivity measurements (CPTU‐R) and measurement of the total penetration resistance, i.e. the total rod friction, together with both geotechnical and chemical analyses on specimens in the laboratory. The results show that electrical imaging can be used for separation of leached soil volumes in marine clays that may form quick clay, from those where the salt content remains too high for this. In the dry crust and thin weathered zone at the top, the resistivity is high but the clay is non‐quick. Also soils with less clay content will have higher resistivity without being quick. The technique may thus be used as a screening tool in order to delimit areas where further investigations are needed from areas that do not require more attention. This has a potential of saving significant resources if used in a relatively early stage of the survey process. It can also increase the overall quality and reliability of the survey results. The induced polarization (IP) results are consistent and seem to be geologically realistic, and appear to contain additional information to the resistivity that is related to material or electrochemical properties, although it is not clear how due to lack of sufficiently detailed reference data. The electrical imaging gives a general picture of the variation in resistivity along soil sections. The CPTU‐R gives variations at depth with very high vertical resolution in one specific location. There is generally good agreement between the models based on electrical imaging and the CPTU‐R. The CPTU‐R results may be used to calibrate the electrical imaging results with quick clay estimations based on rod friction.

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Engineering Geology of Soft Clay

Cited by 14 publications

References 81 publications

Multi‐method geophysical mapping of quick clay

Multi‐method geophysical mapping of quick clay

Geological and Geotechnical Characteristics of Marine Clays at the Busan New Port

Mapping of quick clay using geoelectrical imaging and CPTU‐resistivity

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