Laboratory study on radial consolidation and deformation in clay reinforced with stone columns

Abstract

A series of laboratory tests was performed to study the deformation and radial consolidation around end-bearing (fully penetrating) stone columns. For this purpose, the behaviour of a horizontal slice of a unit cell representative of a column and the surrounding soil was analysed. The tests were carried out in a Rowe–Barden large oedometric cell that was instrumented to measure vertical stresses and pore pressures at several distances from the axis. Two column geometries were tested, with cell-to-column diameter ratios of N = 3 and 4. The most important findings of this work were the rate of pore pressure dissipation, the vertical strain reduction due to the presence of the column of approximately 25% for N = 4 and 35% for N = 3, and the load transfer to the column related to the stiffness ratio between the column and soil resulting in incremental stress concentration factors in the range 2.5 to 9.2. Results were compared with theoretical solutions that are commonly used for the study of stone column behaviour.

Behavior of Compacted Lime — (Well-graded) Soil columns: Large scale tests and numerical modelling

“…The beneficial effects of stone columns on their loadsettlement characteristics of reinforcing soft clay deposits have been widely demonstrated by several researchers (Engelhardt et al, 1974;DiMaggio, 1978;Han and Ye, 2001;McKelvey et al, 2004;Castro and Karstunen, 2010;Murugesan and Rajagopal, 2010;Cimentada et al, 2011;Deb et al, 2011;Fattah et al, 2011).…”

Taş Kolonlarin Oturmalarin Azaltilmasi Etki̇si̇ni̇n Anali̇ti̇k Olarak Değerlendi̇ri̇lmesi̇

“…Toz halindeki kaoline likit limitin (%38) 1.50 katı olan %57 oranında su miktarı ile karıştırılarak kil yapısının bozulması sağlanacaktır. Bu prosedür birçok çalışmada uygulanmıştır [8][9][10][11]. Akışkan ve yapısı bozulmuş kil zemine yeniden yapı kazandırmak için zemin üzerine kademeli yük artışları ile ön konsolidasyon basıncı (30 kPa) uygulanacak ve deneye hazır hale getirilecektir.…”

“…Taş kolon olarak donmuş taş kolonlar üretilecektir. Donmuş kolonlar, tüm kolonda sabit yoğunluğun sağlanabilmesi için literatürde sıkça kullanılan yöntemlerdendir [9,[12][13][14]. Çapı 60 mm ve yüksekliği 150 mm olan donmuş kolonlar, granüler malzemenin kuru yoğunluğu 16.42 kN/m 3 olacak şekilde plastik boru içine sıkıştırılarak oluşturulacaktır.…”

Coupled discrete element–finite difference method for analysing the load-deformation behaviour of a single stone column in soft soil

“…The main purpose of a stone column system are: (i) to transmit foundation loads to a greater depth by a combination of side resistance and end bearing, (ii) to decrease the total and differential settlements, (iii) to decrease the liquefaction potential of fine grained soils, and (iv) to decrease the drainage path for soft soil through radial consolidation under foundation loading (Barksdale and Bachus 1983;Schweiger and Pande 1986;Almgir et al 1996;Tan et al 2008;Deb and Dhar 2011;Ali et al 2012;Babu et al 2012). The deformation of stone columns installed in clay has been the subject of an extensive number of experimental and numerical modelling studies (Poorooshasb and Meyerhof 1997;Ambily and Gandhi 2007;Chai et al 2010;Black et al 2011;Castro and Sagaseta 2011;Cimentada et al 2011;Fattah et al 2011;Sivakumar et al 2011;Castro and Sagaseta 2012;Hanna et al 2013, Han andYe 2002, among others). Stone columns reduce the drainage paths in soft clay, which accelerates consolidation and increases the load carrying capacity due to the subsequent reduction in settlement (Guetif et al 2007;Chai et al 2010;Indraratna et al 2013;Sivakumar et al 2011;Ali et al 2012;Juneja and Mir 2012;Tandel et al 2012).…”