Abstract:
Presence of swelling soils under the foundations of
civil engineering structures particularly lightly
loaded structures has caused serious damages around the globe due to their differential up heaving.
In this paper, based on the results of swell tests on bentonite mixed clay, correlations for predicting
the swelling parameters (i.e., swell potential and swell pressure) have been proposed. Mixing of
bentonite into low swelling clay has imparted significant variations in its index properties including
activity and plasticity index as well as in its swell potential and swell pressure values. Mixing of
bentonite from 0 % to 55% into lean clay (CL) varies its placity index value from 18 to 150 resulting
into variation of its activity from 0.62 to 1.87. For the same range of bentonite addition, the swell
potential and swell pressure values vary from 2.62% to 12.16% and 94 kPa to 928 kPa, respectively.
Based on multiple linear regression analysis of swell and index property test data, correlations
between swelling parameters, activity and remolding moisture content for expansive soils have been
developed. Experimental data of twenty six (26) swelling soils procured from various sites in Pakistan
have been used to validate the proposed correlati
ons. These correlations have predicted the swell
potential and swell pressure of these soils within accuracy of +
10% and +
5%, respectively, in
comparison with their experimentally determined values. A comparison of these predictions with
couple of well-known published empirical equations has also been made.
