Preparation and Long-Term Treatment of Extreme-Soft Soil Using Lime and Polymer

Abstract

Extreme-soft soil prevailed in the field, and preparing and testing such soil in the lab is not without physical challenges. Therefore, the present study aims to prepare extreme-soft soil using commercial bentonite and to treat such soil with different materials for evaluation of long-term performance. The extreme-soft soils, both untreated and treated, were experimentally evaluated by means of a modified vane undrained shear apparatus. Samples of extreme-soft soil are prepared from bentonite ranging from 2% to 10%, to reach this target. There is a separate treatment for the 10% prepared soft adding different lime percentages (up to 20%) and polymer (up to 5%). The soil samples from the treated samples were kept for curing period in open and closed-air conditions for up to 180 days. It has been observed in the study that untreated extreme-soft soil with untreated undrained shear strength between 0.001kPa to 0.0017 kPa correspondingly (bentonite 2% - 10%). Also, at 28 days curing time in a closed-air condition, the 20% lime-treated 10% bentonite extreme-soft soil had gained 1959% undrained shear strength. In addition, the extreme-soft soil treated with 10% bentonite and 5% polymer has 600% greater undrained shear strength than the open-air condition (28 days of curing). Also, at 28 days curing time of 180 days in a closed-air condition, the undrained shear strength of 10% lime-treated 10% bentonite extreme-soft soil has been increased by 1273%.