Serafín Monterrubio

Shallow foundations on expansive soils: a case study of the El Viso Geotechnical Unit, Salamanca, Spain

Construction on expansive soils can generally be resolved using piles. Where shallow foundations are used in these materials, the swelling pressure should be determined and the foundations designed to provide a greater pressure to counteract this. Clearly, it will also be necessary to determine the capacity of the ground to take this load. The paper discusses the bearing capacity of unsaturated expansive soils for a given suction value and notes the bearing capacity was increased by 26% when the effect of suction was taken into account. However, an increase in the water content would cause a decrease in suction and hence a decrease in the bearing capacity.RésuméLa construction sur sols gonflants peut généralement être réalisée à l’aide de pieux. Là où des fondations peu profondes sont mises en œuvre dans ces matériaux, la pression de gonflement devrait être déterminée et les fondations dimensionnées pour apporter une pression supérieure permettant de contrebalancer celle-là. Clairement, il est aussi nécessaire de déterminer la capacité du terrain à supporter ce chargement. L’article discute de la capacité portante de sols gonflants non saturés présentant une valeur de succion donnée et note que la capacité portante est augmentée de 26% quand les effets de la succion sont pris en compte. Cependant, une augmentation de teneur en eau entraînerait une diminution de la succion et de ce fait de la capacité portante.

Serpentinites from Cabo Ortegal (Galicia, Spain): a search for correct use as ornamental stones

Abstract Different varieties of serpentinites present at Cabo Ortegal were studied. For many years, the ‘Verde Pirineos’ type has been quarried and sold commercially, but its physical characteristics do not fulfil the requirements for its use as an ornamental stone. ‘Piedra de Doelo’ is the local name for a serpentinite that has been quarried and used for many centuries in a large number of historical buildings distributed throughout the area. The preservation status of the rock is very poor and the stone is severely affected by weathering. A third variety, similar to the ‘ophicalcite’ described in the literature, is currently under investigation with a view to studying the possibility of the resumption of serpentinite quarrying. Although serpentinites are commercially known as ‘green marbles’, Galician serpentinites do not fulfil the mineral requirements to be described as such. Study of the characteristics of serpentinites, including their mineralogy, may offer a clue to the correct use of Galician serpentinites.