This paper deals with the compositional and textural characteristics determining open metastable structures in the pleistocenic sand outcropping in the Agrigento district (Sicily). The aim of the study was to individuate the bonding types occurring between grains that could generate matric suction phenomena. The composition and microfabric were characterised by means of granulometry, porosimetry, permeability, optical and ESEM-EDS microscopy, thermogravimetry and XR diffractometry, electric conductivity, and ionic chromatography. The data thus acquired show that the skeleton of the sand is constituted mostly by bioclasts and microfossils, calcite and quartz monocrystalline grains. Moreover, assemblages of silt and clay minerals are interposed among them. Cementation is generally absent even at the sites of contact between grains. Porosity is due mainly to interparticle voids. The spatial arrangement of sand, silt and limey grains, the pore geometry, volume and size distribution and network connectivity allow both capillary condensation and effective capillary transport of water. It appears that bonding is due mainly to capillary forces related to the texture and to the type of pores rather than being ruled by composition.

Zimbardo, M., Ercoli, L., & Megna, B. (2016). The open metastable structure of a collapsible sand: fabric and bonding. BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT, 75, 125-139 [10.1007/s10064-015-0752-7].

The open metastable structure of a collapsible sand: fabric and bonding

ZIMBARDO, Margherita
;
ERCOLI, Laura;MEGNA, Bartolomeo
2016

Abstract

This paper deals with the compositional and textural characteristics determining open metastable structures in the pleistocenic sand outcropping in the Agrigento district (Sicily). The aim of the study was to individuate the bonding types occurring between grains that could generate matric suction phenomena. The composition and microfabric were characterised by means of granulometry, porosimetry, permeability, optical and ESEM-EDS microscopy, thermogravimetry and XR diffractometry, electric conductivity, and ionic chromatography. The data thus acquired show that the skeleton of the sand is constituted mostly by bioclasts and microfossils, calcite and quartz monocrystalline grains. Moreover, assemblages of silt and clay minerals are interposed among them. Cementation is generally absent even at the sites of contact between grains. Porosity is due mainly to interparticle voids. The spatial arrangement of sand, silt and limey grains, the pore geometry, volume and size distribution and network connectivity allow both capillary condensation and effective capillary transport of water. It appears that bonding is due mainly to capillary forces related to the texture and to the type of pores rather than being ruled by composition.
Settore ICAR/07 - Geotecnica
Settore GEO/05 - Geologia Applicata
Settore ING-IND/22 - Scienza E Tecnologia Dei Materiali
Zimbardo, M., Ercoli, L., & Megna, B. (2016). The open metastable structure of a collapsible sand: fabric and bonding. BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT, 75, 125-139 [10.1007/s10064-015-0752-7].
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/10447/226731
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