The flow of homogeneous fluids through porous media: analogies with other physical problems

Behaviour of footings on reinforced sand subjected to repeated loading – Comparing use of 3D and planar geotextile

http://wp.kntu.ac.ir/nas_moghaddas/A%20comparison.%20A.pdf

A comparison of static and cyclic loading responses of foundations on geocell-reinforced sand

This paper pertains to the development of a mechanical model to predict the behavior of a geosynthetic-reinforced granular fill over soft soil improved with stone columns. The saturated soft soil has been idealized by Kelvin — Voight model to represent its consolidation behavior. The stone columns are idealized by stiffer springs. Pasternak shear layer and rough elastic membrane represent the granular fill and geosynthetic reinforcement layer, respectively. The nonlinear behavior of the granular fill and the soft soil is considered. Effect of consolidation of the soft soil due to inclusion of the stone columns has also been included in the model. Plane strain conditions are considered for the loading and reinforced foundation soil system. An iterative finite difference scheme is applied for obtaining the solution, and results are presented in nondimensional form. Comparison between the results from the present study and the analytical solution using theory of elasticity shows reasonable agreement. The advantage of using geosynthetic reinforcement is highlighted. Results indicate that inclusion of the geosynthetic layer effectively reduces the settlement. Nonlinearity in the behavior of the soft soil and the granular fill is reduced due to the use of geosynthetic reinforcement layer.

Generalized Model for Geosynthetic-Reinforced Granular Fill-Soft Soil with Stone Columns

A mathematical model to study the soil arching effect in stone column-supported embankment resting on soft foundation soil

The paper pertains to the development of a mechanical model to predict the behaviour of a multilayer geosynthetic-reinforced granular fill soft soil system. The granular fill and the soft soil have been idealised as a Pasternak shear layer and a layer of non-linear springs, respectively. Stretched rough elastic membranes represent the geosynthetic reinforcement layers. The non-linear behaviour of the granular fill and the soft soil is considered. Plane strain conditions are considered for the loading and reinforced foundation soil system. An iterative finite difference scheme is applied for obtaining the solution, and the results are presented in non-dimensional form. The results of the present model are compared with the results of a finite element model. Parametric studies for a uniformly loaded strip footing show the effects of various parameters on the settlement response. Significant reduction of the settlement has been observed as a result of the use of the multilayer geosynthetic reinforcement syst...

Settlement response of a multilayer geosynthetic-reinforced granular fill–soft soil system

The behavior of soil-geosynthetics interfaces depends on the different properties of soil, including particle size, particle shape, density, gravimetric water content, degree of saturation, and properties of geosynthetics that include structure, texture, and other elements. This paper pertains to the study of the influence of the particle shape of sand on the behavior of the sand-geotextile interface. Experiments were conducted using a conventional-sized direct shear box modified for interface testing. In the present study, two different natural sands (one with angular particles and the other with rounded particles) and two different geotextiles were used. The results showed that particle shape significantly influences the interface behavior, especially the postpeak behavior.

Interface Behavior of Woven Geotextile with Rounded and Angular Particle Sand

The paper pertains to a study regarding the response of strip footings resting centrally on the surface of model double-faced wrap-around vertical soil walls. Experiments were performed in the laboratory on small-scale model geosynthetic-reinforced, double-faced, vertical soil walls constructed with sand backfill and wrapped facing using varying spacing, overlap length of reinforcement layers and footing widths to study their effects on its load–deformation behaviour. Then a plane-strain finite element simulation of the model walls was performed, using commercially available Plaxis software, to predict their behaviour under strip loading. Backfill sand and reinforcements were modelled as elastic-perfectly plastic and linearly elastic material, respectively. Comparison of the predicted bearing capacity of the footing resting on these walls and the horizontal displacement of the wall face showed reasonable agreement with the experimental data.

Numerical modelling of surface strip footings resting on double-faced wrap-around vertical reinforced soil walls

The paper presents a mechanical model to predict the behavior of geosynthetic-reinforced granular fill resting over soft soil improved with group of stone columns subjected to circular or axi-symmetric loading. The saturated soft soil has been idealized by spring-dashpot system. Pasternak shear layer and rough elastic membrane represent the granular fill and geosynthetic reinforcement layer, respectively. The stone columns are idealized by stiffer springs. The nonlinear behavior of granular fill and soft soil is considered. Consolidation of the soft soil due to inclusion of stone columns has also been included in the model. The results obtained by using the present model when compared with the reported results obtained from laboratory model tests shows very good agreement. The effectiveness of geosynthetic reinforcement to reduce the maximum and differential settlement and transfer the stress from soft soil to stone columns is highlighted. It is observed that the reduction of settlement and stress transfer process are greatly influenced by stiffness and spacing of the stone columns. It has been further observed that for both geosynthetic-reinforced and unreinforced cases, the maximum settlement does not change if the ratio between spacing and diameter of stone columns is greater than 4.

Axi-symmetric Analysis of Geosynthetic-reinforced Granular Fill-soft Soil System with Group of Stone Columns

The present study involved the development of a mechanical model to study the behaviour of extensible-geosynthetic-reinforced granular fill resting on stone-column-improved soft soil. The stone column, geosynthetic layer, soft soil and granular fill were idealised by stiffer Winkler springs, rough elastic membrane, Kelvin–Voight model and Pasternak shear layer, respectively. Plane strain conditions were considered in the analysis. An iterative finite difference procedure was applied to obtain the solutions and the results are presented in non-dimensional form. The results indicate that inclusion of the geosynthetic layer (inextensible or extensible) effectively reduced the total as well as the differential settlement. However, the use of inextensible geosynthetic reinforcement was more effective than extensible geosynthetic reinforcement to reduce settlement and increase the stress concentration ratio.

P. K. Basudhar

Papers

Settlement response of a multilayer geosynthetic-reinforced granular fill–soft soil system

Interface Behavior of Woven Geotextile with Rounded and Angular Particle Sand

Numerical modelling of surface strip footings resting on double-faced wrap-around vertical reinforced soil walls

Axi-symmetric Analysis of Geosynthetic-reinforced Granular Fill-soft Soil System with Group of Stone Columns

Extensible geosynthetics and stone-column-reinforced soil