Deformation and Stability Analysis of Embankment over Stone Column-Strengthened Soft Ground
- PDF / 2,002,031 Bytes
- 13 Pages / 595 x 786 pts Page_size
- 8 Downloads / 171 Views
pISSN 1226-7988, eISSN 1976-3808 www.springer.com/12205
DOI 10.1007/s12205-020-0349-y
Geotechnical Engineering
Deformation and Stability Analysis of Embankment over Stone Column-Strengthened Soft Ground Ali Ghorbani
a
, Iman Hosseinpour
a
, and Mehdi Shormagea
Civil Engineering Department, Faculty of Engineering, University of Guilan, Rasht, Iran
a
ARTICLE HISTORY
ABSTRACT
Received 26 February 2020 Revised 12 June 2020 Accepted 14 September 2020 Published Online 4 December 2020
Compacted granular columns are commonly used to support embankments over soft soils. Using a reinforcement layer under the embankment causes the total stress to be further transferred to the column rather than soft soil, thus reducing total deformations of the subsoil. In this paper two dimensional (2D) numerical analysis was used to study the influence of stone columns and basal geosynthetic on deformations and stability of an embankment over soft deposit by means of Plaxis 2D finite element code. Unit cell to plane strain conversion approach was applied to transform columns into equivalent walls thus allowing to simulate a full embankment over a group of columns. Comprehensive parametric analysis was then performed to investigate the role of different critical parameters on embankment behavior. Results showed that the use of stone columns yielded the total deformations of the subsoil to significantly reduce, while its influence was less remarkable as a high stiffness geogrid was placed under the embankment. It was also found that the stone column length was the most influential parameter on the embankment total deformations, so that increasing columns length from 0.25Hs to 0.75Hs reduced the vertical and horizontal deformations by about two and five times, respectively. In addition, the use of a high stiffness basal geogrid caused the stability of the embankment to remarkably improve as the value of safety factor at the end of construction increased from 1.25 to about 1.9.
KEYWORDS Geosynthetics Soft soil Stone column Embankment Numerical analysis
1. Introduction Lands composed of soft, saturated sediment layers are problematic due to their low shear strength and high compressibility. The increasing population and lack of suitable ground have inevitably led to the usage of such weak deposits for constructions. Consequently, the application of various soil improvement methods is essential when faced with soft or very soft soils (Mitchell and Huber, 1985; Alfaro et al., 1994). Among various methods available to improve soft soils (e.g., vertical drains, sand wicks, chemical additives, reinforcement, surcharge and vacuum preloading, etc.) ground improvement with an emphasis on the granular column technology overcomes construction problems by reducing the settlement under loading and speeding up the consolidation process (Hosseinpour et al., 2010; Han, 2015b; Al-Bared and Marto, 2017; Mohapatra and Rajagopal, 2017; Almeida et al., 2018; Mahawish et al., 2018; Kadhim et al., 2018; Al-Bared et al., 2019; Lima et al., 2019; Xue et
Data Loading...
