Experimental assessment of the liquefaction resistance of calcareous biogenous sands

liquefaction is a phenomenon in which soils, typically sands, suddenly loose a substantial amount of their shear strength and stiffness, this often triggered by large-magnitude earthquakes. most liquefaction research has focused on silicate-based sands and not on other sand types, such as calcareous biogenous sands calcareous sands are usually composed of skeletal or non-skeletal remains of marine organisms, with unique characteristics in terms of their mineralogy surface roughness, particle shape, crushability, and intraparticle porosity. the unique characteristics of calcareous sands suggest that their geotechnical engineering behaviour can be substantially different compared to that of terrigenous sands, including their behaviour under seismic loading, which have not been very well studied this paper presents the results of an experimental programme aimed at studying the cyclic liquefaction resistance of uncemented calcareous biogenous sands retrieved from south-western puerto rico evaluation of liquefaction potential involved a comprehensive set of isotropically consolidated undrained cyclic triaxial tests on reconstituted samples of this calcareous sand. the programme also included tests on ottawa terrigenous silica sand samples prepared and tested in similar conditions for comparison purposes. in general, the experimental results showed that cabo rojo calcareous sands had higher liquefaction resistance compared to ottawa silica sands tested under similar conditions. important differences between calcareous and silica sands regarding pore pressure generation characteristics and axial strain accumulation were also observed