Cyclic liquefaction screening of sand with non-plastic fines: Critical state
approach
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Abstract
There have been significant advances in the application of critical state, CS, in liquefaction potential
assessment. This was done by comparing state parameter, j with estimated characteristic cyclic stress
ratio, CSR due to an earthquake. A cyclic resistance ratio, CRR curve, which can be determined from cyclic
liquefaction tests, separates historical liquefied and non-liquefied data points (j, CSR). On the other hand,
the concepts of equivalent granular state parameter, j*, which was developed for sands with fines, can be
used in lieu j to provide a unifying framework for characterizing the undrained response of sands with
non/low plasticity fines, irrespective of fines content (fc). The present work combines these two propositions,
and by merely substituting j* for j into the aforementioned CS approach to capture the influence
of fc. A series of static and cyclic triaxial tests were conducted, separately and independently of
the concept of j*, for sand with up to fc of 30%. The clean sand was collected from Sabarmati river belt at
Ahmedabad city in India which was severely affected during the Bhuj earthquake, 2001. The experimental
data gave a single relation for CRR and j* which was then used to assess liquefaction potential for
a SPT based case study, where fc varies along the depth. The prediction matched with the field
observation.
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