A New Finite Element for Back Analysis of a Geogrid Reinforced Soil Retaining Wall Failure

2017 ◽  
Vol 16 (4) ◽  
pp. 435-441 ◽  
Author(s):  
Omid Reza Barani ◽  
Majid Bahrami ◽  
Seyed Amirodin Sadrnejad
Author(s):  
Andrew Lees ◽  
Michael Dobie

Polymer geogrid reinforced soil retaining walls have become commonplace, with routine design generally carried out by limiting equilibrium methods. Finite element analysis (FEA) is becoming more widely used to assess the likely deformation behavior of these structures, although in many cases such analyses over-predict deformation compared with monitored structures. Back-analysis of unit tests and instrumented walls improves the techniques and models used in FEA to represent the soil fill, reinforcement and composite behavior caused by the stabilization effect of the geogrid apertures on the soil particles. This composite behavior is most representatively modeled as enhanced soil shear strength. The back-analysis of two test cases provides valuable insight into the benefits of this approach. In the first case, a unit cell was set up such that one side could yield thereby reaching the active earth pressure state. Using FEA a test without geogrid was modeled to help establish appropriate soil parameters. These parameters were then used to back-analyze a test with geogrid present. Simply using the tensile properties of the geogrid over-predicted the yield pressure but using an enhanced soil shear strength gave a satisfactory comparison with the measured result. In the second case a trial retaining wall was back-analyzed to investigate both deformation and failure, the failure induced by cutting the geogrid after construction using heated wires. The closest fit to the actual deformation and failure behavior was provided by using enhanced fill shear strength.


2012 ◽  
Vol 188 ◽  
pp. 60-65
Author(s):  
Fu Lin Li ◽  
Fang Le Peng

The combined effects of the rate-dependent behavior of both the backfill soil and the geosynthetic reinforcement have been investigated, which should be attributed to the viscous property of material. A nonlinear finite element method (FEM) analysis procedure based on the Dynamic Relaxation method was developed for the geosynthetic-reinforced soil retaining wall (GRS-RW). In the numerical analysis, both the viscous properties of the backfill and the reinforcement were considered through the unified nonlinear three-component elastic-viscoplastic model. The FEM procedure was validated against a physical model test on geosynthetic-reinforced soil retaining wall with granular backfill. Extensive finite-element analyses were carried out to investigate the tensile force distributions in geosynthetic reinforcement of geosynthetic-reinforced soil retaining wall under the change of loading rate. It is found from the analyses that the presented FEM can well simulate the rate-dependent behavior of geosynthetic-reinforced soil retaining wall and the tensile force of geosynthetic reinforcement arranged in retaining wall.


2012 ◽  
Vol 594-597 ◽  
pp. 266-269
Author(s):  
Fu Lin Li ◽  
Fang Le Peng

On the basis of the Dynamic Relaxation method, a nonlinear finite element method (FEM) analysis procedure was developed for the geosynthetic-reinforced soil retaining wall. The FEM procedure technique incorporated the unified three-component elasto-viscoplastic constitutive model which can consider the rate-dependent behavior of both the backfill soil and the geosynthitic reinforcement. A simulation was performed on a physical model test on geosynthetic-reinforced soil retaining wall to validate the presented FEM. Extensive finite-element analyses were carried out to investigate the earth pressure distributions from the back of retaining wall under variable rate loading. It is shown that this FEM can well simulate the rate-dependent behavior and the earth pressure of geosynthetic-reinforced soil retaining wall.


2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Xingli Jia ◽  
Jinliang Xu ◽  
Yuhai Sun

In order to reveal the main factors affecting the deformation of reinforced soil retaining wall and the influence of various factors on the deformation, the constitutive relation is discretized into four aspects of soil, geogrid, wall panel, and contact surface, and discrete element matrices are, respectively, constructed, with the method of separate finite element. Based on the finite element geotechnical analysis technology platform, the deformation analysis model of reinforced soil retaining wall is established. Taking the modulus of foundation soil as the influencing factor of the foundation soil, taking the geogrid stiffness, length, and spacing as the influencing factors of geogrids, and taking the filling type of limestone, fly ash, and silty clay as the influencing factors of backfill in the wall, the horizontal and vertical deformations of reinforced retaining wall under different factors using the methods of controlling a single variable analysis are calculated. The results show that the increase of elastic modulus of foundation soil will reduce the vertical deformation of the wall but increase the horizontal deformation. The silty clay is not suitable as filler, and lime soil is slightly better than fly ash. The spacing between geogrids is 20 cm ~ 60 cm, which has less effect on wall deformation, but the horizontal deformation rapidly increases after the spacing increases to 80 cm, and other grid performance influencing factors also have the characteristic, where there exists a threshold. The wall will have a greater deformation when the threshold is not reached; a higher indicator of the grid to reduce the deformation of the retaining wall is not obvious after reaching the threshold.


Author(s):  
Ripon Hore ◽  
Sudipta Chakraborty ◽  
Ayaz Mahmud Shuvon ◽  
Md. Fayjul Bari ◽  
Mehedi A. Ansary

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