The Mechanical Response of a Silty Sand Stabilized with Colloidal Silica

Antigoni Vranna,Theodora Tika

doi:10.3390/geotechnics1020013

Abstract

This paper presents a laboratory investigation into the mechanical response of a silty sand, with a fines content of 10%, stabilized with colloidal silica (CS). To this end, a series of unconfined compression tests as well as monotonic and cyclic triaxial tests was performed on a silty sand, comprising a mixture of a clean sand and a silty sand, stabilized with two concentrations of CS. The effect of various parameters on the behaviour of the stabilized silty sand was studied, such as CS concentration, soil density, and the presence of fines. The test results were compared with the corresponding of the untreated silty sand as well as the parent clean sand. It is shown that stabilization, even at the lowest CS = 6% concentration studied, significantly improves the undrained shear strength as well as the liquefaction resistance of the stabilized silty sand. Both the monotonic and cyclic response of the stabilized soil are only slightly affected by density. Furthermore, cyclic straining up to at least 5% of double-amplitude axial strain does not influence the undrained shear strength of the stabilized silty sand.

Highlights

Passive stabilization is a non-disruptive soil improvement technique for the mitigation of liquefaction potential of sands under existing developed structures [1]
Among the various stabilizers employed for passive stabilization, such as sodium silicate [7], laponite suspensions [8], and bio-materials [9], colloidal silica has received increasing interest in the past years for the reasons described below
The aim of this paper is the investigation of how the presence of fines affects the monotonic and cyclic response of a colloidal silica (CS)-stabilized sand

Summary

Introduction

Passive stabilization is a non-disruptive soil improvement technique for the mitigation of liquefaction potential of sands under existing developed structures [1]. The concept of this technique comprises slow injection of a stabilizing material at the upgradient side of a developed site by means of natural or augmented groundwater flow [2]. The stabilizing material has initially low viscosity, and injection is performed effortlessly and, unlike grouting processes, under low pressure [3]. Passive stabilization is considered non-destructive and causes minimum disturbance at the normal operations of the developed site under treatment [1,6], contrary to other soil improvement techniques, such as vibratory methods, underpinning, and grouting. Among the various stabilizers employed for passive stabilization, such as sodium silicate [7], laponite suspensions [8], and bio-materials [9], colloidal silica has received increasing interest in the past years for the reasons described below

Objectives

Methods

Conclusion